* Filter available contacts for a notification to be verified
  contacts belonging to the user
* New better code for handling label queries
* Some better help text for notification forms
* Remove old notification forms and views

New model functionality, better forms and views.

Separate phone and email contacts, add verification of contact
information, improve views and forms.

Also squash migrations in the alerts app.

Previously forgot to add deepclean and gwhen robot users to the
LVC group.

Traefik can pass the subject and issuer in a 'cert-infos'
header, so I am adding an authentication backend to use that.

Non-priority production containers will use the master for
writes and a read-replica database for reads. This commit adds
functionality for getting the replica's information from
environment variables and sets up a database routing scheme.

As shown here: emfollow/userguide!23

As requested here: emfollow/gwcelery!359