Correctly proxy exception in frontend_proxy worker

Fix up pusher logging a bit

Fix state cache invalidation on workers

Make sure that users' changes to the config files are preserved.

Fixes #4440.

We're counting the number of push notifications, but not the number of badges;
I'd like to see if they are significant.

* You need an entry in the debian changelog (and not a regular newsfragment)
  for debian packaging changes.
* Regular newsfragments must end in full stops.

I suspect the CPU usage metrics for this are going to /dev/null at the moment.

* Added HAProxy example

Proposal of an example with HAProxy. Asked by #4541.

Signed-off-by: Benoît S. (“Benpro”) <gitlab@benpro.fr>

* Following suggestions of @richvdh

Prevent crash on pagination.

Migration Script: consider e2e_room_keys.is_verified column as boolean

This column was considered as an int, crashing the whole
migration process

Signed-off-by: Eric <eric@pedr0.net>

Fixup generated metrics config

I just got bitten by a file being caught by the .gitignore, which shouldn't
have been, and am now pissed off with the .gitignore. I have basically declared
bankruptcy on it and started again.

Attempt to clarify installation/config instructions

* Move RegistrationHandler init to HomeServer

* Move post registration actions to RegistrationHandler

* Add post regisration replication endpoint

* Newsfile

* Run unit tests against python 3.7

... so that we span the full range of our supported python versions

* Switch to xenial

* fix psql fail

* pep8 etc want python 3.6