This extends the collection with support for seamless authentication at the Jitsi server using Matrix OpenID.

1. New role for installing the [Matrix User Verification Service](https://github.com/matrix-org/matrix-user-verification-service)
2. Changes to Jitsi role: Installing Jitsi Prosody Mods and configuring Jitsi Auth
3. Changes to Jitsi and nginx-proxy roles: Serving .well-known/element/jitsi from jitsi.DOMAIN
4. We updated the Jitsi documentation on authentication and added documentation for the user verification service.

* Add task to configure a standalone JVB on a different server

* add missing file

* set nginx config

* update prosody file and expose port 5222

* change variable name to server id

* formatting change

* use server id of jvb-1 for the main server

* adding documentation

* adding more jvbs

* rename variable

* revert file

* fix yaml error

* minor doc fixes

* renaming tags and introducing a common tag

* remove duplicates

* add mapping for jvb to hostname/ip

* missed a jvb_server

* Update roles/matrix-nginx-proxy/templates/nginx/conf.d/matrix-jitsi.conf.j2

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* PR review comments and additional documentation

* iterate on dict items

* Update docs/configuring-playbook-jitsi.md

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Update docs/configuring-playbook-jitsi.md

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Update docs/configuring-playbook-jitsi.md

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Update docs/configuring-playbook-jitsi.md

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Update docs/configuring-playbook-jitsi.md

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Update docs/configuring-playbook-jitsi.md

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Update docs/configuring-playbook-jitsi.md

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* adding documentation around the xmpp setting

* add common after

* reduce the number of services during init of the additional jvb

* remove rogue i

* revert change to jitsi init as it's needed

* only run the jvb service on the additional jvb host

* updating docs

* reset default and add documentation about the websocket port

* fix issue rather merge with master

* add missing role introduced in master

* this role is required too

* Adding new jitsi jvb playbook, moving setup.yml to matrix.yml and creating soft link

* updating documentation

* revert accidental change to file

* add symlink back to roles to aid running of the jitsi playbook

* Remove extra space

* Delete useless playbooks/roles symlink

* Remove blank lines

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

This paves the way for installing other roles into `roles/galaxy` using `ansible-galaxy`,
similar to how it's done in:

- https://github.com/spantaleev/gitea-docker-ansible-deploy
- https://github.com/spantaleev/nextcloud-docker-ansible-deploy

In the near future, we'll be removing a lot of the shared role code from here
and using upstream roles for it. Some of the core `matrix-*` roles have
already been extracted out into other reusable roles:

- https://github.com/devture/com.devture.ansible.role.postgres
- https://github.com/devture/com.devture.ansible.role.systemd_docker_base
- https://github.com/devture/com.devture.ansible.role.timesync
- https://github.com/devture/com.devture.ansible.role.vars_preserver
- https://github.com/devture/com.devture.ansible.role.playbook_runtime_messages
- https://github.com/devture/com.devture.ansible.role.playbook_help

We just need to migrate to those.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1393

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1057

Jitsi-meet enabled websockets by default, claiming better reliability.
Matrix-nginx-proxy configuration has been set up according to the
Prosody documentation: https://prosody.im/doc/websocket

**HSTS Preloading:**
In its strongest and recommended form, the [HSTS policy](https://www.chromium.org/hsts) includes all subdomains, and indicates a willingness to be “preloaded” into browsers:
`Strict-Transport-Security: max-age=31536000; includeSubDomains; preload`

**X-Xss-Protection:**
`1; mode=block` which tells the browser to block the response if it detects an attack rather than sanitising the script.

Mostly affects people who disable the integrated `matrix-nginx-proxy`.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/456
and more specifically 4d62a75f6f.

Not sure if it breaks with them or not, but no other directive
uses quotes and the nginx docs show examples without quotes,
so we're being consistent with all of that.

Code was clean up and simplified to make it simpler and easier to
maintain. No features were modified.

The different configurations are now all lower case, for consistent
naming.

`matrix_nginx_proxy_ssl_config` is now called
`matrix_nginx_proxy_ssl_preset`. The different options for "modern",
"intermediate" and "old" are stored in the main.yml file, instead of
being hardcoded in the configuration files. This will improve the
maintainability of the code.

The "custom" preset was removed. Now if one of the variables is set, it
will use it instead of the preset. This will allow to mix and match more
easily, for example using all the intermediate options but only
supporting TLSv1.2. This will also provide better backward
compatibility.

A new variable called `matrix_nginx_proxy_ssl_config` is created for
configuring how the nginx proxy configures SSL. Also a new configuration
validation option and other auxiliary variables are created.

A new variable configuration called `matrix_nginx_proxy_ssl_config` is
created. This allow to set the SSL configuration easily using the
default options proposed by Mozilla. The default configuration is set to
"Intermediate", removing the weak ciphers used in the old
configurations.

The new variable can also be set to "Custom" for a more granular control.
This allows to set another three variables called:

- `matrix_nginx_proxy_ssl_protocols`,
- `matrix_nginx_proxy_ssl_prefer_server_ciphers`
- `matrix_nginx_proxy_ssl_ciphers`

Also a new task is added to validate the SSL configuration variable.

Hopefully fixes a regression caused by b106a9592e.

Related to #597 (Github Pull Request).

Fixes #417 (Github Issue)

Use Jinja2 lstrip_blocks option in templates to ensure consistent
indentation in generated files.

This makes all containers (except mautrix-telegram and
mautrix-whatsapp), start as a non-root user.

We do this, because we don't trust some of the images.
In any case, we'd rather not trust ALL images and avoid giving
`root` access at all. We can't be sure they would drop privileges
or what they might do before they do it.

Because Postfix doesn't support running as non-root,
it had to be replaced by an Exim mail server.

The matrix-nginx-proxy nginx container image is patched up
(by replacing its main configuration) so that it can work as non-root.
It seems like there's no other good image that we can use and that is up-to-date
(https://hub.docker.com/r/nginxinc/nginx-unprivileged is outdated).

Likewise for riot-web (https://hub.docker.com/r/bubuntux/riot-web/),
we patch it up ourselves when starting (replacing the main nginx
configuration).
Ideally, it would be fixed upstream so we can simplify.

Fixes #83 (Github issue)

It hasn't mattered much to have these so far, but
it's probably a good idea to have them.

With this change, the following roles are now only dependent
on the minimal `matrix-base` role:
- `matrix-corporal`
- `matrix-coturn`
- `matrix-mailer`
- `matrix-mxisd`
- `matrix-postgres`
- `matrix-riot-web`
- `matrix-synapse`

The `matrix-nginx-proxy` role still does too much and remains
dependent on the others.

Wiring up the various (now-independent) roles happens
via a glue variables file (`group_vars/matrix-servers`).
It's triggered for all hosts in the `matrix-servers` group.

According to Ansible's rules of priority, we have the following
chain of inclusion/overriding now:
- role defaults (mostly empty or good for independent usage)
- playbook glue variables (`group_vars/matrix-servers`)
- inventory host variables (`inventory/host_vars/matrix.<your-domain>`)

All roles default to enabling their main component
(e.g. `matrix_mxisd_enabled: true`, `matrix_riot_web_enabled: true`).
Reasoning: if a role is included in a playbook (especially separately,
in another playbook), it should "work" by default.

Our playbook disables some of those if they are not generally useful
(e.g. `matrix_corporal_enabled: false`).

As suggested in #63 (Github issue), splitting the
playbook's logic into multiple roles will be beneficial for
maintainability.

This patch realizes this split. Still, some components
affect others, so the roles are not really independent of one
another. For example:
- disabling mxisd (`matrix_mxisd_enabled: false`), causes Synapse
and riot-web to reconfigure themselves with other (public)
Identity servers.

- enabling matrix-corporal (`matrix_corporal_enabled: true`) affects
how reverse-proxying (by `matrix-nginx-proxy`) is done, in order to
put matrix-corporal's gateway server in front of Synapse

We may be able to move away from such dependencies in the future,
at the expense of a more complicated manual configuration, but
it's probably not worth sacrificing the convenience we have now.

As part of this work, the way we do "start components" has been
redone now to use a loop, as suggested in #65 (Github issue).
This should make restarting faster and more reliable.

The new container image is about 20x smaller in size, faster to start up, etc.

This also fixes #26 (Github issue).

Adds support for managing certificates manually and for
having the playbook generate self-signed certificates for you.

With this, Let's Encrypt usage is no longer required.

Fixes Github issue #50.