ldap-registration-proxy is already connected to the homeserver
container's network by default (via group vars), so there's no need for this.

This also makes it handle the `/_matrix/client/v3/register` endpoint,
not just `/_matrix/client/r0/register`

This reverts commit bf95ad2235.

This was a bad idea.
It's better to have people manually define the password.

Otherwise, `matrix_homeserver_generic_secret_key` changing some day in
the future would break the bot and one would have to figure out how to
reset its password manually.

Using an explicit password is more stable.

Running just `setup-all,start` is not enough, because it doesn't run `ensure-matrix-users-created`
and the bot account won't get created.

* chore(deps): update signal bridge version + config

* style(deps): rename default note to self config variable

* Add to_json for additional safety

---------

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

This is split out from matrix-cactus-comments (see 241779b583),
but also heavily inspired by `matrix-static-files`.

The container image has only ever been available for amd64,
so not enabling self-building for the other architectures was a mistake
that orignally landed in:
https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2089

Looks like these variables were originally named this way in
https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2089

Related to https://github.com/mautrix/discord/issues/95

This probably never even worked anyway and was a leftover copy/paste
from some other role.

The docs (`docs/configuring-playbook-bridge-mautrix-wsproxy.md`) only
talk about `matrix_mautrix_wsproxy_hostname`, which was only used via
Traefik labels. The endpoint exposed via `matrix-nginx-proxy` (`/_matrix/wsproxy`)
hasn't been mentioned anywhere.