Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Overall the playbook uses the expression "Add the following configuration to your `inventory/host_vars/matrix.DOMAIN/vars.yml` file:" with the heading "Adjusting the playbook configuration" for sections to explain what to be added as variables

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Provoked by https://github.com/mother-of-all-self-hosting/mash-playbook/pull/280

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2524

This role is usable on its own and it's not tied to Matrix, so
extracting it out into an independent role that we install via
ansible-galaxy makes sense.

This also fixes the confusion from the other day, where
`matrix_postgres_*` had to be renamed to `devture_postgres_*`
(unless it was about `matrix_postgres_backup_*`).
We now can safely say that ALL `matrix_postgres_*` variables need to be
renamed.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2305

Related to:

- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1727
- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1754
- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1755
- https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/467

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/868

- removed build_database_list.yml