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

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

This is consistent with what all other roles do. If someone includes a
role, the assumption is that they want its functionality enabled.

The playbook distribution then disables components via
`group_vars/matrix_servers`. We've always had `matrix_grafana_enabled: false`
there, so flipping the in-role `_enabled` flag to `true` does not change
anything for playbook users. Users who import the roles individually in
their own other playbooks (and who don't use `group_vars/matrix_servers`)
may observe a change in the defaults with this.

Using `matrix_synapse_*` variables within the `matrix-grafana` role
is not a good practice.

We now have a `matrix_grafana_default_home_dashboard_path` variable
with a good universal default value and we override it via
`group_vars/matrix_servers` based on enabled components, etc.

This is a better fix for https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2133

We shouldn't be using it in the role (`tasks/setup.yml`) without
defining at least some default value in the role itself.

We've always had the override in `group_vars/matrix_servers`,
so the variable was essentially defined (at the playbook level), but
that's not the right way to do things.

Reason: during a fresh install, when there is no synapse yet, systemd unit fails to start, thus whole play fails

* send emails in UTF-8 👋
* fix options descriptions
* add SMTP auth
* allow sending emails from your apps and scripts using postmoogle as email provider

- 0.9.9 (https://github.com/matrix-org/dendrite/releases/tag/v0.9.9)

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2114

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2108

`ephemeral_events`` and `sync_with_custom_puppets` have been flipped
to keep up with the default upstream config:
b33bd9c4a7

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2105

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

This keeps the configuration cleaner and hopefully prevents odd issues
if Synapse (by any chance) happens to interpret `pusher_instances: []`
as "no pushers", instead of as "push from the master process".

I haven't confirmed what an empty pushers/federation-senders list means,
so it's safer to just avoid it.

.. 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.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2101

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2089

We do the same everywhere else. This is an omission.