to prevent docker from using dir instead of file

Using the older one likely leads to issues like #517.

added docs, added seperate service for database, pr comments

better path handling, fixed some mistakes

Fix/mx puppet bridge

Update postgres (12.2 -> 12.3, etc)

enable by default v2 api prefix for ma1sd

We can undo this once https://github.com/ma1uta/ma1sd/issues/44 gets
resolved.

Related to #508 (Github Pull Request).

Jitsi 4548-1 update

Typo STMP -> SMTP

Prevent 404s when Riot tries to retrieve domain-specific config.json

Riot unconditionally asks for a config.${document.domain}.json, c.f.
https://github.com/vector-im/riot-web/blame/develop/src/vector/getconfig.ts#L24

Document how to administer synapse database via tunneled web-frontend

Fixes #494 (Github Issue).

Add note about ask-become-pass

This flag is necessary for Ansible to ask for the sudo password when using the non-root option as documented in the `hosts` file. Otherwise, Ansible errors out with `missing sudo password`.

Fix typo in validation

This is mostly here to guard against problems happening
due to server migration and doing `chown -R matrix:matrix /matrix`.

Normally, the file is owned by `1000:1000`, as expected.

If ownership changes, Dimension could still start, but it will fail the
first time it tries to write to the database. Explicitly chowning
before startup guards against this.

Related to #485 and #486 (Github Pull Requests).
Also related to ccc7aaf0ce.