Document how to administer synapse database via tunneled web-frontend

Fixes #494 (Github Issue).

Add note about ask-become-pass

This flag is necessary for Ansible to ask for the sudo password when using the non-root option as documented in the `hosts` file. Otherwise, Ansible errors out with `missing sudo password`.

Fix typo in validation

This is mostly here to guard against problems happening
due to server migration and doing `chown -R matrix:matrix /matrix`.

Normally, the file is owned by `1000:1000`, as expected.

If ownership changes, Dimension could still start, but it will fail the
first time it tries to write to the database. Explicitly chowning
before startup guards against this.

Related to #485 and #486 (Github Pull Requests).
Also related to ccc7aaf0ce.

Dimension runs as the `node` user in the container (`1000:1000`).
It doesn't seem like we have a way around it. Thus, its configuration
must also be readable by that user (or group, in this case).

We don't really need to fail in such a spectactular way,
but it's probably good to do. It will only happen for people
who are defining their own user/group id, which is rare.

It seems like a good idea to tell them that this doesn't work
as they expect anymore and to ask them to remove these variables,
which otherwise give them a fake sense of hope.

Related to #486 (Github Pull Request).

Related to #485 (Github Pull Request).

Remove default UID/GID

If one runs the playbook with `--tags=setup-all`, it would have been
fine.

But running with a specific tag (e.g. `--tags=setup-riot-web`) would
have made that initialization be skipped, and the `matrix-riot-web` role
would fail, due to missing variables.

Added a documentation enhancement regarding external TURN server

Clarify domain of Dimension admin users in docs by using matrix_domain variable

Update coturn (4.5.1.1 -> 4.5.1.2)

fix skype bridge being rebuilt when upstream changed

No migration steps should be required.

This should be a no-op, no migration necessary.

Ansible will migrate the ownership of the base path and config path, but
manual intervention will be required in order to migrate the ownership
of files in those directories (i.e. dimension.db).

Stop the services:

  (local)$ ansible-playbook -i inventory/hosts setup.yml --tags=stop

Fix the permissions on the server:

  (server)# chown -Rv "{{ matrix_user_username }}:{{ matrix_user_username }}" "{{ matrix_dimension_base_path }}"

which would typically look like:

  (server)# chown -Rv matrix:matrix /matrix/dimension/

Reconfigure Dimension and start the services:

  (local)$ ansible-playbook -i inventory/hosts setup.yml --tags=setup-dimension,start

Add caddy 1 well-known example

Adjust params

Document how to point dimension jitsi widgets at your own jitsi instance

Add support for Jitsi LDAP authentication

This can be removed once turt2live/matrix-dimension#345 is resolved.

Fixes the example, to add the missing required configuration key
for the HTTP policy provider.

Related to #477 (Github Issue).

Update matrix-appservice-irc to 0.16.0

Note the potential breaking change

Resolves #474

* add permalinkPrefix to riot-web config

* add feature to change default theme of riot-web via its config file

* remove matrix_riot_web_change_default_theme and provide sane default

Add information to make jitsi work with a client in LAN

Update Jitsi docker images to stable 4416

We've had reports of the `:latest` tag not working anymore,
leading to an error as described here:
https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/341