Restructure rest and service modules

[joeshannon]

As suggested in https://github.com/DiamondLightSource/blueapi/pull/538#discussion_r1674033258

• src
  • blueapi
  • service
    • rest
    • main
    • openapi
    • worker
    • main (formerly interface)
    • runner
    • model

[stan-dot]

@callumforrester , @DiamondJoseph what are your thoughts?

[callumforrester]

Agree this should be done as a low priority

[stan-dot]

I must say it feels a bit underspecified at the moment @callumforrester . the difference between what we have now is very minimal - once the handler was removed

[callumforrester]

That's understandable, to add justification, our current structure is:

• service
  • interface
  • main
  • model
  • openapi
  • runner

Which is confusing, main and interface are the top-level runtimes for each process, but that's not obvious. The proposed structure makes it more obvious.