This change adds a new 'scenarios' section to the configuration
documentation, with an initial 'all in one' scenario.

Change-Id: Ibe9cbbb59e2f72b18fdeb493feb085735edbbf8c
Story: 2004360
Task: 27960

This allows us to add configuration scenarios.

Change-Id: Id636f78c61237fb27fa65fa3d4b3fc1a4cf0ba6a
Story: 2004360
Task: 40777

Adds support for enabling TLS on the Docker registry.

Change-Id: Idac6a1dfb17f4a22b3043531d1181a5585cafe6a
Story: 2007952
Task: 40428

Task: 39811

Change-Id: I6f065073feee42b2a0921a4aea98f7004fe5f7bf

Adds information on tuning Ansible, including forks, SSH pipelining and
fact caching.

Change-Id: I83d1469c62d63390222750d9d1f6e337e45b2373
Story: 2007492
Task: 39447

Clearly not very user friendly at the moment. We probably want to
include these files as part of test.

Change-Id: Ib6ed0e68b55a98920cbaf3e8ec828901b4b9ed9f
Story: 2004291
Task: 37810

Depends-On: https://review.opendev.org/690559/

Change-Id: I4e766424607317e5817d26461f7a1e180e9b2146
Story: 2004337
Task: 37378
Task: 37381

Change-Id: I0074b8ef2153813b3ffdd5e8254d76df25e49302
Story: 2004337
Task: 28486

Change-Id: I2962d148afb77834f78deedf206060b86445055a
Story: 2004337
Task: 27924

Change-Id: I267a65137910b71540aba6ea79f475607f5e2e98
Story: 2004337
Task: 27923