Move away from CS Studio Eclipse: discuss approach - Mark 2 [Late summer/autumn 2023]

Following on from https://github.com/ISISComputingGroup/IBEX/issues/7665, we should decide what the long term plans for our GUI are.

In https://github.com/ISISComputingGroup/IBEX/issues/7665 we decided that we would *not* proceed with the implementation of the compatibility layer. Therefore 4 remaining options still need to be discussed and a path forwards chosen:

1. Do nothing, maintain CSS ourselves
2. ~[DISCARDED] Use e(fx)clipse compatibility layer~
3. Re-write IBEX as a standalone JavaFX application which happens to use some phoebus views
4. Re-write IBEX-specific views as phoebus "plugins" (in JavaFX)
5. Migrate IBEX gui to some other technology

Slides summarising each approach are available at `\\isis\shares\ISIS_Experiment_Controls\data for tickets\Ticket7665`

### Acceptance criteria

- Path forwards is discussed again, and a conclusion reached about which option we want to choose in the medium/long term.