Autosave: investigate whether autosave can be split up within IOCs

It would be helpful to be able to have separate autosave files for different axes/sensors on various IOCs. This would be a more general solution to the problem addressed in https://github.com/ISISComputingGroup/IBEX/issues/2831.

The IOCs which stand out as particularly relevant for this are the ones which define a variable number of DB records, such as:
- Galil axes
- Eurotherm sensors
- Mk3 choppers
- Genesys
- Danfysik

This ticket should investigate whether this is possible and document the mechanism to do it. If it is possible, a new ticket should be created to do this on all the relevant IOCs.