This:

- brings consistency - no more mixing `_name_prefix` and `_registry_prefix`
- adds extensibility - a future patch will allow reconfiguring all registry prefixes for all roles in the playbook

We still have `_docker_` vs `_container_` inconsistencies.
These may be worked on later.

* Add a global config option for Docker network MTU

* Upgrade systemd_docker_base (v1.2.0-0 -> v1.3.0-0)

The new version includes `devture_systemd_docker_base_container_networks_driver_options`
due to 3cc7d12396

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3502

* Switch from passing matrix_playbook_docker_network_mtu to respecting devture_systemd_docker_base_container_networks_driver_options

Related to:
- 3cc7d12396
- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3502

* Update all roles to versions that respect `devture_systemd_docker_base_container_networks_driver_options`

---------

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

This is actually authored by Julian Foad here
(https://lab.trax.im/matrix/matrix-docker-ansible-deploy), but was in
need of a rebase and various adjustments caused by huge playbook
refactoring that landed in the past months.

This rework is completely untested.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/266