Remove/re-use/replace "deviceFunctions" source kind

[tpoliaw]

SourceKind, used to distinguish between imported modules currently has three variants.

• planFunctions for modules containing plans
• dodal for modules containing device functions that are called via dodal's make_all_devices and assume DeviceInitializationControllers
• deviceFunctions the previous version for devices that is now an alias for dodal.

Now that there is about to be an alternative to dodal modules in the device manager, should we

1. Create a new source type, deviceManager to support the new loading
2. Convert all beamlines at once and use dodal for the new loading
3. Stop deviceFunctions delegating to dodal and use it for the new loading

I'm currently erring towards 1. I think 2 would cause chaos and we should have at least a brief transition period where both are supported. 3 could work but are any beamlines currently relying on it being an alias to dodal?

If we don't re-use deviceFunctions, could we remove it entirely?

[DiamondJoseph]

Added the 2.0.0 milestone for removing the deviceFunctions enum

[tpoliaw]

Depending on how soon 2.0 is likely to be, we could remove dodal as the same time. If we're removing the dodal dependency it'd be a major version bump whenever it did end up happening

[DiamondJoseph]

I think we (y'all) can start thinking about 2.0 in the new year, we've got a big enough shopping list now:
https://github.com/DiamondLightSource/blueapi/milestone/19