This mostly fixes `key-order` warnings around
`block` statements.

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`frontend_proxy` workers have been superseded by `generic_worker` workers.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 an attempt to make ansible-lint happy.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1939

This commit adds a 'matrix-ntfy' role that runs Ntfy server in Docker with
simple configuration, and plumbing to add the role to the playbook.

TODO: documentation, self-check, database persistence.

`localhost` may resolve to `::1` on some IPv6-enabled systems, which will
not work, because we only potentially expose container ports on
`127.0.0.1` when nginx is disabled (`matrix_nginx_proxy_enabled: false`),
not on `::1`.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1914

> Error:   19:3      error    wrong indentation: expected 4 but found 2  (indentation)

Fixup for ba51997f7b

We redefine these variables in `group_vars/matrix_servers`, but it's better
to have some defaults in the role as well.

.. regardless of whether matrix-nginx-proxy runs in a container or not

When setting `matrix_nginx_proxy_enabled: false` and enabling authentication on the metrics endpoint, the htpasswd file is hardcoded to the nginx-proxy container dir, this changes the hardcoded value to a variable so the path can be updated

People often report and ask about these "failures".
More-so previously, when the `docker kill/rm` output was collected,
but it still happens now when people do `systemctl status
matrix-something` and notice that it says "FAILURE".

Suppressing to avoid further time being wasted on saying "this is
expected".

For an unknown reason prometheus ignored the given "numeric" index and replaced it by 1. This made it not work properly, plus multiple workers of same types were not differentiable. With a "string" index, it works as intended.

* Add support for obtain ECDSA keys

* Replace matrix_ssl_lets_encrypt_use_ecdsa_keys for matrix_ssl_lets_encrypt_key_type

Reverts b1b4ba501fdfaa, 90c9801c560b6, a3c84f78ca9c65a, ..

I haven't really traced it (yet), but on some servers, I'm observing
`ansible-playbook ... --tags=start` completing very slowly, waiting
to stop services. I can't reproduce this on all Matrix servers I manage.
I suspect that either the systemd version is to blame or that some
specific service is not responding well to some `docker kill/rm` command.

`ExecStop` seems to work great in all cases and it's what we've been
using for a very long time, so I'm reverting to that.