Fixes #586 (Github Issue)

Fixes #579 (Github Issue).

Fixes #539 (Github Issue).

There's no change in the source code. Just a release bump for packaing
reasons. It doesn't matter much for us here, but let's be on the latest
tag anyway.

· needs documentation; no checks yet for port clashes or typos in worker name
· according to https://github.com/matrix-org/synapse/wiki/Workers-setup-with-nginx#results
  about 90% of requests go to the synchrotron endpoint
· thus, the synchrotron worker is especially suited to be load-balanced
· most of the other workers are documented to support only a single instance
· https://github.com/matrix-org/synapse/blob/master/docs/workers.md

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.

Regression since #362 (Github Pull Request).

Synapse v1.9.0 changed some things which made the REST Auth Password
Provider break.

The ma1uta/matrix-synapse-rest-password-provider implements some
workarounds for now and will likely deliver a proper fix in the future.

Not much has changed between the 2 projects, so this should be a
painless transition.

Related to #355.

Can you double check that the way I have this set only exposes it locally? It is important that the manhole is not available to the outside world since it is quite powerful and the password is hard coded.