This adds https://github.com/matrix-org/matrix-doc/pull/2409 to the
appservice registrations, enabling synapse to push EDUs to appservices.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/806

Fixes a problem like this:
> File "/usr/lib/python3.8/site-packages/mautrix/bridge/e2ee.py", line 79, in __init__
> raise RuntimeError("Unsupported database scheme")

mautrix-python's e2ee.py module expects to find `postgres://` instead of
`postgresql://`.

This makes the `sqlite://` URI match what we were using before
and what the config expects.

Looks like there are some that I missed in 087dbe4ddc

I was thinking that it makes sense to be more specific,
and using `_postgres_` also separated these variables
from the `_database_` variables that ended up in bridge configuration.

However, @jdreichmann makes a good point
(https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/740#discussion_r542281102)
that we don't need to be so specific and can allow for other engines (like MySQL) to use these variables.

I don't use this bridge, so this is completely untested.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/716

This patch makes us use more fully-qualified container image names
(either prefixed with docker.io/ or with localhost/).

The latter happens when self-building is enabled.

We've recently had issues where if an image was removed manually
and the service was restarted (making `docker run` fetch it from Docker Hub, etc.),
we'd end up with a pulled image, even though we're aiming for a self-built one.
Re-running the playbook would then not do a rebuild, because:
- the image with that name already exists (even though it's something
else)
- we sometimes had conditional logic where we'd build only if the git
repo changed

By explicitly changing the name of the images (prefixing with localhost/),
we avoid such confusion and the possibility that we'd automatically pul something
which is not what we expect.

Also, I've removed that condition where building would happen on git
changes only. We now always build (unless an image with that name
already exists). We just force-build when the git repo changes.

Related to #451 (Github Issue).

This keeps the roles cleaner and more independent of matrix-base,
which may be important for people building their own playbook
out of the individual roles and not using the matrix-base role.

# Auth server config
        auth:
            # Publicly accessible base URL for the login endpoints.
            # The prefix below is not implicitly added. This URL and all subpaths should be proxied
            # or otherwise pointed to the appservice's webserver to the path specified below (prefix).
            # This path should usually include a trailing slash.
            public: http://example.com/login/
            # Internal prefix in the appservice web server for the login endpoints.
            prefix: /login

I've been thinking of doing before, but haven't.

Now that the Whatsapp bridge does it (since 4797469383),
it makes sense to do it for all other bridges as well.
(Except for the IRC bridge - that one manages most of registration.yaml by itself)

We do use some `:latest` images by default for the following services:
- matrix-dimension
- Goofys (in the matrix-synapse role)
- matrix-bridge-appservice-irc
- matrix-bridge-appservice-discord
- matrix-bridge-mautrix-facebook
- matrix-bridge-mautrix-whatsapp

It's terribly unfortunate that those software projects don't release
anything other than `:latest`, but that's how it is for now.

Updating that software requires that users manually do `docker pull`
on the server. The playbook didn't force-repull images that it already
had.

With this patch, it starts doing so. Any image tagged `:latest` will be
force re-pulled by the playbook every time it's executed.

It should be noted that even though we ask the `docker_image` module to
force-pull, it only reports "changed" when it actually pulls something
new. This is nice, because it lets people know exactly when something
gets updated, as opposed to giving the indication that it's always
updating the images (even though it isn't).