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

We try to only use console logging (going to journald) for everything,
instead of logging things twice (or more).

While it's kind of nice having it, it's also somewhat raw
and unnecessary.

Having a good default and not even mentioning it seems better
for most users.

People who need a more exposed bridge (rare) can use
override the default configuration using
`matrix_mautrix_signal_configuration_extension_yaml`.