This paves the way for installing other roles into `roles/galaxy` using `ansible-galaxy`,
similar to how it's done in:

- https://github.com/spantaleev/gitea-docker-ansible-deploy
- https://github.com/spantaleev/nextcloud-docker-ansible-deploy

In the near future, we'll be removing a lot of the shared role code from here
and using upstream roles for it. Some of the core `matrix-*` roles have
already been extracted out into other reusable roles:

- https://github.com/devture/com.devture.ansible.role.postgres
- https://github.com/devture/com.devture.ansible.role.systemd_docker_base
- https://github.com/devture/com.devture.ansible.role.timesync
- https://github.com/devture/com.devture.ansible.role.vars_preserver
- https://github.com/devture/com.devture.ansible.role.playbook_runtime_messages
- https://github.com/devture/com.devture.ansible.role.playbook_help

We just need to migrate to those.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1894

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1894

* Make interface hidden behind proxy by default

* Remove expose option and replace with http_bind_port

Reasoning: This is a similar binary trigger but allows to bin not on all interfaces

* Clarify maubot admin purpose

* Remove unnecessary edif

* Extend docs to prevent common misconceptions

* Make http_bind_port singular, do not allow multiple values

* Make optional again

This shall indicate that the public url of maubot is here configured the same as matrix_server_fqn_matrix but this must not be the case.
In the config I used the matrix fqnd directly as this part of the config is directly bound to the homeserver we want to connect to (but can not use the internal)

The /data is hardcoded in the container

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

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