Clarify hosts file wording

Self-hosted Etherpad

Update IRC bridge to 0.23.0

Add double quotes 'matrix-postgres-init-additional-db-user-and-role.sql.j2' template

Fixed missing quotes

Use Debian Buster Docker repo on Debian Bullseye

Future maintainer: check on https://docs.docker.com/engine/install/debian/ if Docker for
Debian 11 is released, then undo this commit

Add mx-puppet-skype and mx-puppet-slack to README

I also moved matrix-sms-bridge up to match the order from container-images.md

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/682

Name the Synapse database on state compression import

Fixes:
https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/833

The default scalar.vector.im integrations manager doesn't support custom
URL's for etherpad, therefore Dimension needs to be enabled.

Regression since f6097fbba1

Fixes a regression introduced in f6097fbba1fb, which was cauing Synapse
to die with this error message:

> ValueError: sender_localpart needs characters which are not URL encoded.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/806

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.

Correct some typos in FAQ

I don't think this was causing an issue, but it might
if the bot token has a more special value in the future.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/828

This needs to be added for WebSocket upgrades to work properly (see doc:
http://nginx.org/en/docs/http/websocket.html)

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/795
and https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/822

A better fix will come later: https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/825

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/824