Generalize flat and arc commands

We currently have iic expose flat/arc and iic scienceFlat/Arc commands, which were simply ported over from the earlier LAM-specific software, and so expect to control the DCB lamps. Control of the pfiCalib lamps will be very similar,and has been partly accounted for.

In the meanwhile, we do need to take SuNSS "flats", where icc does nothing with lamps, but basically just arranges for the DATA-TYP to be set right.