Implement Architecture v3

[garethbowen]

History:

v1: No containerization - every service running in the host OS running medic-os v2: Partial containerization - every service in a single Docker container based on medic-os v3: Full containerization - every service running in its own Docker container based on a 3rd party distro

Draft proposal: https://docs.google.com/document/d/12dne30_k0zvBSdnY_gkvbwfheFFqTvmwQCJutAKX45U/edit

[garethbowen]

Relevant branch for this work: https://github.com/medic/cht-core/tree/deconstruct-3.7.0

[garethbowen]

This is now ready for AT!

It's a little bit different from usual as it's already merged to master so just test it there. Another way it's different from usual is we're very short on documentation, so many of the steps here will need more detail from engineers in order to complete.

Because there's a lot to test and to give us a space to collaborate, I've created a doc for AT requirements.

[garethbowen]

This has been merged, and ATed, though as it's such a broad issue testing will be ongoing. Closing as complete.