Moxa configurator: extend to managing multiple moxas

As a user I would like to be able to manage the accessible IP settings for multiple moxas using a single instance of the web service developed in https://github.com/ISISComputingGroup/IBEX/issues/7490 - because not all moveable moxas necessarily have an associated PC on which it is sensible to run this web service.

To do:
- Get the list of MOXAs that can be managed from somewhere. Maybe a central service publishes a list of "moveable" items?
- Allow the user to select a MOXA from this list (e.g. using a drop down menu)
- New settings should apply to the selected MOXA.

Follows on from https://github.com/ISISComputingGroup/IBEX/issues/7490