Fixup for 7e2e2626a0

Some references were left unrenamed which caused `validate_config.yml`
to trigger.

This role is usable on its own and it's not tied to Matrix, so
extracting it out into an independent role that we install via
ansible-galaxy makes sense.

This also fixes the confusion from the other day, where
`matrix_postgres_*` had to be renamed to `devture_postgres_*`
(unless it was about `matrix_postgres_backup_*`).
We now can safely say that ALL `matrix_postgres_*` variables need to be
renamed.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2305

Supersedes https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2256

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2256

Regression since https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2290

More details about the new key type can be found here:
https://eff-certbot.readthedocs.io/en/stable/using.html#rsa-and-ecdsa-keys

Existing RSA-based keys will continue to renew as RSA until manual
action is taken. Example from the documentation above:
> certbot renew --key-type ecdsa --cert-name example.com --force-renewal

In the future, we may add a command which does this automatically for
all domains.

This is done via devture_systemd_service_manager_services_list_auto
already.

We expect `--tags=start` to handle systemd reloading, so we don't need
to do it manually each time we install/uninstall a .service file.

* added dendrite captcha options

* added hcaptcha doc

* proper url

* Apply suggestions from code review

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

* Update main.yml

* renamed captcha vars to new naming scheme

* change vars to new format

* Rename back some incorrect renamed variables

These variables are either not just part of the `client_api` subsection,
or are not even part of that section at all. They shouldn't have been
renamed in baaef2ed616e2645550d9

* Fix up naming inconsistencies

Some of these variables had been renamed in one place,
but not in other places, so it couldn't have worked that way.

* Add validation/deprecation for renamed Dendrite variables

Related to 4097898f885cf4c73, baaef2ed616e2645550, 68f4418092fa8ad
and a0b4a0ae6b2f1f18

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

- forego removing Docker images - it's not effective anyway, because it
  only removes the last version.. which is a drop in the bucket, usually

- do not reload systemd - it's none of our business. `--tags=start`,
  etc., handle this

- combine all uninstall tasks under a single block, which only runs if
  we detect traces (a leftover systemd .service file) of the component.
  If no such .service is detected, we skip them all. This may lead to
  incorect cleanup in rare cases, but is good enough for the most part.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2297

* Exempt Matrix server from ntfy rate limit

Add the matrix fqdn and localhost to ntfy's exemption list.
Also allow all ntfy rate limits to be configured through Ansible
variables.

* Fix names and formatting

* fixes

* tabs not spaces

* Lint

* Use raw tags instead of bracket soup

We had checks to avoid stopping/deleting systemd services for workers
that used to exist and will continue to exist, but we were deleting
config files for workers each time.. Only to recreate them again later.

This lead to:

- too many misleading "changed" tasks
- too much unnecessary work
- potential failures during playbook execution possibly leaving the
  system in a bad state (no worker config files)