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.

* Draupnir for all Role

* Draupnir for all Documentation

* Pin D4A to Develop until D4A patches are in a release.

* Update D4A Docs to mention pros and cons of D4A mode compared to normal

* Change Documentation to mention a fixed simpler provisioning flow.

Use of /plain allows us to bypass the bugs encountered during the development of this role with clients attempting to escape our wildcards causing the grief that led to using curl.

This reworded commit does still explain you can automatically inject stuff into the room if you wanted to.

* Emphasise the State of D4A mode

* Link to Draupnir-for-all docs and tweak the docs some

* Link to Draupnir-for-all from Draupnir documentation page

* Announce Draupnir-for-all

---------

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

main.yml is not included due to that its changed separately.

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/1939