BBA Changes

[T-Nicholls]

Changes made while attempting to get BBA to interface with the virtac.

[T-Nicholls]

The Python 3.7 build is failing due to pytest-flake8 which is abandoned, it's not worth fixing it on its own as it'd be resolved whenever we move ATIP over to the Diamond pip-skeleton/ copier template/new deployment system.

[MJGaughran]

If you're able to be more explicit about the cause of errors with other cothread applications, I would suggest adding that but otherwise this PR is good.

[T-Nicholls]

I don't think I can elaborate concisely on the issue with other cothread applications.

Side note, I noticed that the fix for the issue in AT that was blocking us from making I04 the default ring mode got merged, so I've updated it and snuck it on the end of this pr.

Also, for some reason, I don't have merge permissions for this repo or Pytac, but I do for dls-bba