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

The general idea here is that config examples should just have a hash and no
extraneous whitespace, both to make it easier for people who don't understand
yaml, and to make the examples stand out from the comments.

Batch cache invalidation over replication

Test against Postgres 9.5 as well as 9.4

Support .well-known delegation when issuing certificates through ACME

Split /login into client_reader

* fix to use makeContext so that we don't need to rebuild the certificateoptions each time

Transfer bans on room upgrade

Postgres 9.5 is the first to support UPSERTs, so we should really run against
it as well as 9.4.