This is based on the PR (https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3241)
by Tobias Diez (https://github.com/tobiasdiez).

I've refactored some parts, made it more configurable, polished it up,
and it's integrated into the playbook now.

Both the WeChat bridge and WeChat agent appear to be working.
The WeChat bridge joins rooms and responds as expected.

That said, end-to-end testing (actually bridging to a WeChat account) has not been done yet.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/701

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3092

This is sponsored https://etke.cc/ work related to https://gitlab.com/etke.cc/ansible/-/issues/2

Squashed commit of the following:

commit fdd37f0247
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 21:05:53 2024 +0300

    Add documentation for WeChat bridge

commit 8426fc8b95
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 20:59:42 2024 +0300

    Rename directory for matrix_wechat_agent_container_src_files_path

commit da200df82b
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 20:58:26 2024 +0300

    Make WeChat listen_secret configurable and auto-configured via matrix_homeserver_generic_secret_key

commit 4022cb1355
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 20:54:56 2024 +0300

    Refactor install.yml for WeChat a bit (using blocks, etc.)

commit d07a39b4c4
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 20:52:35 2024 +0300

    Rename WeChat Agent configuration file

    This makes it more clear that it belongs to the agent.
    Otherwise, `config.yaml` and `configure.yaml` make you wonder.

commit ccca72f8d1
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 20:49:06 2024 +0300

    Move WeChat agent configuration to a template

commit a4047d94d8
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 20:47:17 2024 +0300

    Mount WeChat config as readonly and instruct bridge to not update it

commit bc0e89f345
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 20:46:33 2024 +0300

    Sync WeChat config with upstream

    Brings up-to-date with:
    https://github.com/duo/matrix-wechat/commits/0.2.4/example-config.yaml

commit a46f5b9cbc
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 19:48:17 2024 +0300

    Rename some files

commit 3877679040
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 19:47:10 2024 +0300

    Update WeChat logging config

    This brings it up-to-date with what mautrix-go uses.
    Otherwise, on startup we see:

    > Migrating legacy log config

    .. and it gets migrated to what we've done here.

commit e3e95ab234
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 19:43:37 2024 +0300

    Make sure matrix-wechat-agent runs as 1000:1000

    It needs to write stuff to `/home/user/.vnc`.

    `/home/user` is owned by `user:group` (`1000:1000`), so it cannot run
    any other way.

    Previously, if the `matrix` user was uid=1000 by chance, it would work,
    but that's pure luck.

commit 4d5748ae9b
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 18:57:09 2024 +0300

    Pin wechat and wechat-agent versions

commit 40d40009f1
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 18:53:58 2024 +0300

    docker_image -> container_image for WeChat bridge

commit cc33aff592
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 18:00:25 2024 +0300

    docker_src -> container_src in WeChat bridge

commit 42e6ae9a64
Author: Slavi Pantaleev <slavi@devture.com>
Date:   Mon Jun 3 17:54:24 2024 +0300

    matrix_go_wechat_ -> matrix_wechat_

    The bridge is written in Go, but does not include Go anywhere in its
    name. As such, it's mostly useless to use `matrix_go_wechat` as the
    prefix.

commit d6662a69d1
Author: Tobias Diez <code@tobiasdiez.de>
Date:   Mon Mar 25 10:55:16 2024 +0800

    Add wechat bridge

This paves the way for installing other roles into `roles/galaxy` using `ansible-galaxy`,
similar to how it's done in:

- https://github.com/spantaleev/gitea-docker-ansible-deploy
- https://github.com/spantaleev/nextcloud-docker-ansible-deploy

In the near future, we'll be removing a lot of the shared role code from here
and using upstream roles for it. Some of the core `matrix-*` roles have
already been extracted out into other reusable roles:

- https://github.com/devture/com.devture.ansible.role.postgres
- https://github.com/devture/com.devture.ansible.role.systemd_docker_base
- https://github.com/devture/com.devture.ansible.role.timesync
- https://github.com/devture/com.devture.ansible.role.vars_preserver
- https://github.com/devture/com.devture.ansible.role.playbook_runtime_messages
- https://github.com/devture/com.devture.ansible.role.playbook_help

We just need to migrate to those.

With this change, the following roles are now only dependent
on the minimal `matrix-base` role:
- `matrix-corporal`
- `matrix-coturn`
- `matrix-mailer`
- `matrix-mxisd`
- `matrix-postgres`
- `matrix-riot-web`
- `matrix-synapse`

The `matrix-nginx-proxy` role still does too much and remains
dependent on the others.

Wiring up the various (now-independent) roles happens
via a glue variables file (`group_vars/matrix-servers`).
It's triggered for all hosts in the `matrix-servers` group.

According to Ansible's rules of priority, we have the following
chain of inclusion/overriding now:
- role defaults (mostly empty or good for independent usage)
- playbook glue variables (`group_vars/matrix-servers`)
- inventory host variables (`inventory/host_vars/matrix.<your-domain>`)

All roles default to enabling their main component
(e.g. `matrix_mxisd_enabled: true`, `matrix_riot_web_enabled: true`).
Reasoning: if a role is included in a playbook (especially separately,
in another playbook), it should "work" by default.

Our playbook disables some of those if they are not generally useful
(e.g. `matrix_corporal_enabled: false`).

As suggested in #63 (Github issue), splitting the
playbook's logic into multiple roles will be beneficial for
maintainability.

This patch realizes this split. Still, some components
affect others, so the roles are not really independent of one
another. For example:
- disabling mxisd (`matrix_mxisd_enabled: false`), causes Synapse
and riot-web to reconfigure themselves with other (public)
Identity servers.

- enabling matrix-corporal (`matrix_corporal_enabled: true`) affects
how reverse-proxying (by `matrix-nginx-proxy`) is done, in order to
put matrix-corporal's gateway server in front of Synapse

We may be able to move away from such dependencies in the future,
at the expense of a more complicated manual configuration, but
it's probably not worth sacrificing the convenience we have now.

As part of this work, the way we do "start components" has been
redone now to use a loop, as suggested in #65 (Github issue).
This should make restarting faster and more reliable.