IBEX GUI: add a label for IOC per instrument and show in IOC list

As a scientist I would like a way of adding/editing and showing a label for an IOC for equipment that doesn't typically move around or change purpose, such as "sample changer" for a specific Galil IOC. This could be shown in the IOC list in either/both the add/remove IOC screen or start/stop IOC screen.

### Acceptance Criteria
- [ ] A way of storing this information is used to set/get the label which is persistent to instrument regardless of configuration
- [ ] A way of adding/editing this label is created
- [ ] A way of viewing this label alongside the IOC name in the IOC lists is created.

### Extra Information
There may be a PV that exists for this that we aren't using - Freddie has some information on this.

## How to Test
(**Add before making a PR**)