This allows people to augment the Synapse image with custom tools and
addons without having to rebuild it from scratch.

If customizations are enabled, the playbook will build a new
`localhost/matrixdotorg/synapse:VERSION-customized` image
on top of the default one (`FROM matrixdotorg/synapse:VERSION`)
and with custom Dockerfile build steps.

For servers that self-build the Synapse image, the Synapse image will be
built first, before proceding to extend it the same way.

In the future, we'll also have easy to enable Dockerfile build steps
for modules that the playbook supports.

In the future, we'll also inject media storage providers that we support
into the `matrix_synapse_media_storage_providers_auto` list.

If someone is using Dendrite and enabling Grafana, we'll no longer
download Synapse dashboards.

If someone is not using node-exporter, we'll no longer download node
exporter dashboards.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2133

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2103

.. although.. manual configuration is discouraged in most cases.

As stream writer workers are also powered by the `generic_worker`
Synapse app, this necessitated that we provide means for distinguishing
between them and regular `generic_workers`.

I've also taken the time to optimize nginx configuration generation
(more Jinja2 macro usage, less duplication).

Worker names have also changed.
Workers are now named sequentially like this:
- `matrix-synapse-worker-0-generic`
- `matrix-synapse-worker-1-stream-writer-typing`
- `matrix-synapse-worker-2-pusher`

instead of `matrix-synapse-worker_generic_worker-18111` (indexed with a
port number).

People who modify `matrix_synapse_workers_enabled_list` directly will
need to adjust their configuration.

`frontend_proxy` workers have been superseded by `generic_worker` workers.
Related to https://github.com/matrix-org/synapse/pull/13645

This is done in anticipation of this option's removal in the
upcoming Synapse v1.66.0 release (likely tomorrow).

See: https://matrix-org.github.io/synapse/v1.66/upgrade.html#delegation-of-email-validation-no-longer-supported

* appservice: add and use matrix_homeserver_* vars

* appservice: use the new vars

* Apply suggestions from code review

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

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

Now that https://github.com/digitalentity/matrix_encryption_disabler/pull/9
has been merged, we can get the module from there.

Continuation of 246c43be1e

Source: https://github.com/matrix-org/synapse/blob/v1.59.0/docs/upgrade.md#deprecation-of-the-synapseappappservice-and-synapseappuser_dir-worker-application-types

As an alternative, we should probably find a way to run one or a few
more generic workers (which will handle appservice and user_dir stuff) and
update `homeserver.yaml` so that it would point to the name of these workers using
`notify_appservices_from_worker` and `update_user_directory_from_worker` options.

For now, this solves the deprecation, so we can have a peace of mind
going forward.

We're force-setting these worker counts to 0, so that we can clean up
existing homeservers which use these worker types. In the future, these
options will either be removed or repurposed (so that they transparently
create more generic workers that handle user_dir/appservice loads).

This switches the playbook from devture/rust-synapse-compress-state (a
container image which wraps the upstream-prebuilt amd64 binary of
rust-synapse-compress-state) to registry.gitlab.com/mb-saces/rust-synapse-compress-state
(https://gitlab.com/mb-saces/rust-synapse-compress-state), which builds
rust-synapse-compress-state from source and provides a multi-arch image
that currently works on amd64 and arm64.

Ideally, we'll stop using `:latest` and arm32 support will be made
available upstream as well at some point.
Discussed here: https://gitlab.com/mb-saces/rust-synapse-compress-state/-/issues/1

This makes it easier to use another container image for
rust-synapse-compress-state, which may be storing the binary at another
path.

This is a minor hotfix, needs to be bumped though or new deploys will break (existing deploys not affected by bug).