Put waiting logic on device side

[DominicOram]

DiamondLightSource/hyperion#248 added some logic for waiting to check that our scan was valid. However, we shouldn't be doing this polling waiting in the plan, instead we should refactor the device so that we can use bps.wait in the plan. We have copied all over the code now, and they should all be updated to a nicer pattern:

• wait_for_det_to_finish_moving

Note

• We might be able to use https://blueskyproject.io/ophyd/reference/positioners.html for this

[DominicOram]

Same is true for wait_for_det_to_finish_moving

[DominicOram]

Arm/Disarm done in DiamondLightSource/hyperion#749