Add apple2 energy device to i06

[Relm-Arrowny]

see DiamondLightSource/sm-bluesky#195 for detail and task list.

Major different to other apple2 is they store their polynomial in epics pv.
Implementation options:

• We can generate an lookup table from epic on start up and use the standard Apple2Controller with a generated lookup.
• As they only have one single polynomial for the entire energy range we could just define an EnergyMotorConvertor device for i06 that read and store the parameters on creation.

[oliwenmandiamond]

I personally think the best way is to implement a EnergyMotorLookupDevice which extends EnergyMotorLookup. This will add the epics signals and methods to construct the LUT and then we can use the generic Apple2Controller which doesn't need to worry about implementation of how it gets the LookupTable