Move bridges into separate roles

Add a variable to control the stop tasks

Reasoning is the same as for matrix-org/synapse#5023.

For us, the journal used to contain `docker` for all services, which
is not very helpful when looking at them all together (`journalctl -f`).

Fix case of the mxisd ldap.connection.baseDNs option in matrix_mxisd_configuration_extension_yaml comment

Provide a sample rest_auth_endpoint close to actual setup

Fix matrix_synapse_ext_password_provider_ldap_start_tls (it's boolean)

The goal is to move each bridge into its own separate role.
This commit starts off the work on this with 2 bridges:
- mautrix-telegram
- mautrix-whatsapp

Each bridge's role (including these 2) is meant to:

- depend only on the matrix-base role

- integrate nicely with the matrix-synapse role (if available)

- integrate nicely with the matrix-nginx-proxy role (if available and if
required). mautrix-telegram bridge benefits from integrating with
it.

- not break if matrix-synapse or matrix-nginx-proxy are not used at all

This has been provoked by #174 (Github Issue).

Add a task to stop services (and remove containers)

Move around options on updating-users-passwords.md

and provide an example for using the admin API

Mention the Synapse User Admin API on updating-users-passwords.md

The bit about the matrix-make-user-admin script was messed up (it wasn't actually a code block so the "<username>" was hidden). For me at least it seems like the ``` syntax is much harder to accidentally mess up.

Bump postgres versions

Bump riot-web version (1.0.8->1.1.0)

Fix matrix-synapse example for Caddy

Mautrix facebook

Docs for #161 (Github issue) and #168 (Github Pull Request).

Add option to proxy 3pid registration endpoints

Add registrations_require_3pid synapse option

Update URL for Matrix federation tester

The previous URL returns a 404.