Update docs related to installation: minor edits

- Reduce width of the table for DNS configuration

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

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

Partially reverts ac26cc1cb0.

The configurability introduced there is still available, so people can
easily disable this, if necessary.

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

This is done for a few reasons:

- less globals and more indepdendence for each role is better. We rely
  on various externally-hosted roles and they don't rely on this global
  either.

- `matrix_container_global_registry_prefix` could make people think they
  could just override this variable and have all their images pull from
  elsewhere. This is rarely the case, unless you've taken special care
  to mirror all the various components (from their respective
  registries) to your own. In such a case, you probably know what you're
  mirroring and can adjust individual variables.

- nowadays, various components live on different registries.
  With Docker Inc tightening rate limits for Docker Hub, it's even more
  likely that we'll see increased diversity in where images are hosted

Update docs: add copyright headers

Add license information to files for MX bridges

Those authors were picked up based on the current status (dae0f44603), the others (around 30 people whose contributions have been removed) being grouped as "MDAD project contributors".

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

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

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

As the future for the MX bridges in this playbook and by themselves seems uncertain, this commit adds license information in SPDX format to the files for those bridges, before the bridges would be deprecated and possibly get removed from the project.

Please note that .license files are added for the files which would be broken if such information are added as header, following the REUSE's specification.

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

`-t` works on both old and new Docker versions, so it's best to use that.

Related to ac26cc1cb0 which disabled
`3478/udp` by default.

Without this patch, homeservers continued to advertise the `3478/udp` port,
even though it was no longer exposed. While clients should handle that
gracefully (by falling back to TCP, etc.), it seems like Element either
doesn't do that or it doesn't support TCP (which this patch won't fix).

In any case, it's better to only announce what is actually supported/exposed.

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

Update docs/ansible.md: copy from the MASH project and minor changes

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

It was copied from 2bc4cc45d7/docs/ansible.md

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

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

Update dependency Sphinx to v8.2.1

It's useless and just makes the config longer.