Galil: Home multiple axes at the same time

As someone using Galils in IBEX I would like to be able to home more than one axis at a time without errors and with it ending reliably in order to save time when homing axes on an instrument.

### Acceptance Criteria
- [ ] More than one axis can be homed at once on a Galil

### Extra Information
- This is currently not possible as there are various errors, as well as the need to manage the threads for the homing in an appropriate way.
- This will need some investigation into the Galil and the homing routines as they are at the moment, this may be best timeboxed rather than attempting to point the completion because of this.
- There is a script on IMAT which homes multiple motors sequentially which at least simplifies the process somewhat.
- The specific example given was for SANS and to home for example at least 2 adjacent slits (e.g. North and East, or North and West).
- Whilst it is unlikely to be able to home all 8 axis at once, being able to home multiples would be beneficial as two sets of four will take less time than all 8 in sequence for example, so setting a limit on the number of axes which can be homed together is acceptable at this point.
- https://github.com/ISISComputingGroup/ibex_developers_manual/wiki/Galil-homing-routines might help.

_Where required files/links are_

## How to Test
_verbose instructions for reviewer to test changes
(**Add before making a PR**)_
tiem in planning 00:32 23/5/24