examples of the ophyd-async device creation process and reasoning

[stan-dot]

That would be good as well, but I think having examples in the docs without having to read through the code would be helpful for setting up new environments.

Originally posted by @tpoliaw in https://github.com/DiamondLightSource/blueapi/pull/408#issuecomment-2199487149

[callumforrester]

@stan-dot could you add more description/context to this issue please?