Update release (release-0.30.0 -> release-0.31.0)

Fix incorrect docker version tag for matrix-appservice-irc

https://github.com/matrix-org/matrix-appservice-irc/releases/tag/0.30.0

https://github.com/matrix-org/matrix-appservice-irc/releases/tag/0.29.0

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1108

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1070

Related discussion here: 1ab507349c (commitcomment-51108407)

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1070

Signed-off-by: Ahmad Haghighi <haghighi@fedoraproject.org>

These are just defensive cleanup tasks that we run.
In the good case, there's nothing to kill or remove, so they trigger an
error like this:

> Error response from daemon: Cannot kill container: something: No such container: something

and:

> Error: No such container: something

People often ask us if this is a problem, so instead of always having to
answer with "no, this is to be expected", we'd rather eliminate it now
and make logs cleaner.

In the event that:
- a container is really stuck and needs cleanup using kill/rm
- and cleanup fails, and we fail to report it because of error
suppression (`2>/dev/null`)

.. we'd still get an error when launching ("container name already in use .."),
so it shouldn't be too hard to investigate.

The git module will create it anyway, but that would likely use `root:root`.

> WARNING: Error loading config file: .dockercfg: $HOME is not defined

.. which appeared in Docker 20.10.

We'll be adding `.timer` units later on, so it's good to be
more explicit.

If a service is enabled, a database for it is created in postgres with a uniqque password. The service can then use this database for data storage instead of relying on sqlite.

The Docker 19.04 -> 20.10 upgrade contains the following change
in `/usr/lib/systemd/system/docker.service`:

```
-BindsTo=containerd.service
-After=network-online.target firewalld.service containerd.service
+After=network-online.target firewalld.service containerd.service multi-user.target
-Requires=docker.socket
+Requires=docker.socket containerd.service
Wants=network-online.target
```

The `multi-user.target` requirement in `After` seems to be in conflict
with our `WantedBy=multi-user.target` and `After=docker.service` /
`Requires=docker.service` definitions, causing the following error on
startup for all of our systemd services:

> Job matrix-synapse.service/start deleted to break ordering cycle starting with multi-user.target/start

A workaround which appears to work is to add `DefaultDependencies=no`
to all of our services.

This is both for consistency with 93cc71cb69976c
and for making things more obvious.

Depending on the distro, common commands like sleep and chown may either
be located in /bin or /usr/bin.

Systemd added path lookup to ExecStart in v239, allowing only the
command name to be put in unit files and not the full path as
historically required. At least Ubuntu 18.04 LTS is however still on
v237 so we should maintain portability for a while longer.

No migration steps should be required.

Note the potential breaking change

Resolves #474

This fixes an incorrect indentation in the database specification for
appservice-irc which caused matrix-appservice-irc to refuse to start
with the remarkably unhelpful error message:

```
ERROR:CLI Failed to run bridge.
```

This also updates doc links to the new matrixdotorg repo because the
tedomum repo contains out-of-date documentation.

This change allows us to work with both our existing Docker image
(`tedomum/matrix-appservice-irc:latest`) and with the
official Docker image (`matrixdotorg/matrix-appservice-irc`).

The actual change to the official Docker image requires more testing
and will be done separately.