Create PV showing whether ISIS is in cycle [TIMEBOX: 2.5 days]

As part of the discussion for https://github.com/ISISComputingGroup/IBEX/issues/7626, we decided that it would be useful to have a facility PV that displays whether ISIS is currently in cycle. In the first instance, this would be useful for triggering automated utility scripts used to maintain the shared instrument scripts repo which we want to run once after every cycle, as discussed in the ticket linked above.

### Acceptance Criteria
- [ ] We have a single facility wide PV showing the current In Cycle status of the ISIS Facility

### Extra Information
- Depends on: https://github.com/ISISComputingGroup/IBEX/issues/7915
- ~This PV should likely come from Accelerator Controls, This ticket might just be sending an email asking them to create this PV~ See Freddie's comment

## How to Test
_verbose instructions for reviewer to test changes
(**Add before making a PR**)_

Start by reading issues 7626 and 7915, then review Freddie's comment to determine whether the PV should be provided by Accelerator Controls or created in IBEX. Confirm the facility-wide In Cycle status source and dependency before implementing. Done means one facility PV exposes the current status and the issue includes concrete testing instructions.

Scritto dal modello di indicizzazione a partire dal testo della issue.