Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2086

Remove appservice database setup/config as the latest update no longer requires it.

This is probably a continuation of changes made in d7ed672f7.

.. instead of `['']`.

The final result in the `env` file will be the same (`POSTMOOGLE_ADMINS=`)
in both cases, but it's better to avoid confusion.

This is done in anticipation of this option's removal in the
upcoming Synapse v1.66.0 release (likely tomorrow).

See: https://matrix-org.github.io/synapse/v1.66/upgrade.html#delegation-of-email-validation-no-longer-supported

We do this for all other supported homeservers.

A "public by default" homeserver is a bad idea for most people.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2076

* postmoogle: add admins

* postmoogle: update jija2 defaults

* postmoogle: fix typo

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2068

Possibly fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2060

Regression since 3f8cb96a18 - https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2048

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2057

Regression since the mass-replace in 34cdaade0.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2054

* appservice: add and use matrix_homeserver_* vars

* appservice: use the new vars

* Apply suggestions from code review

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

Before this, it was trying to pull the `latest` git branch.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2043

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

Related to https://github.com/jitsi/docker-jitsi-meet/issues/1377

Adding this doesn't really help though. `stable-7648-2` is broken
regardless. `stable-7648-3` is necessary to make it work.

We're already updated to `-3` anyway. This just adds the missing
environment variable for completeness.