Fixes #106 (Github Issue).

We recently had a report of the Postgres backup container's log file
growing the size of /var/lib/docker until it ran out of disk space.

Trying to prevent similar problems in the future.

Certain more-minimal Debian installations may not have
lsb-release installed, which makes the playbook fail.

We need lsb-release on Debian, so that ansible_lsb
could tell us if this is Debian or Raspbian.

Update certbot (1.6.0 -> 1.7.0)

Update nginx (1.19.1 -> 1.19.2)

Update postgres versions (12.3 -> 12.4, etc)

Undo ill-advised change

In #628 I proposed a CORS change that turns out not to be the root of the issue. Caffeine-addled diagnosis leads to sloppy thinking, and this change should be reverted. In fact, if left it will cause problems for new installations.

Update CORS for ma1sd

Even with the v2 updates listed in #503 and partially addressed in #614, this is still needed to enable identity services to function with Element Desktop/Web. Testing on multiple clients with a clean config has confirmed this, at least for my installation.

Update README.md -> 'many times' -> 'more than once'

Stating "many times" makes me think there is a finite amount of times I can run it before it *will* start causing trouble. But this is not true. So just state it can me ran more than once without causing trouble :)

Python requires docker package and other small improvements

Related to #620 (Github Pull Request).

Allow self-build images for Synapse-Admin

Hopefully fixes a regression caused by b106a9592e.

Related to #597 (Github Pull Request).

Add a secondary option on how to get access token

Enable ma1sd hashing by default

Replace gpg dependency for gnupg for debian compatibility

Potentially the CURLing could be a better approach, since then you don't leave spare sessions hanging.

Make ansible check mode runs silent, for non idempotent tasks