Containers: put an existing ISIS IOC into container

This follows on from #8096

Discussed 10/07/2025 1:32:30

As a developer I would like to eventually be able to migrate to Linux and this will likely involve containerising our IOCs so we can gradually run things under a Linux environment.

I suggest picking a simple TCP-comms IOC such as a lakeshore 372 for this.

This ticket will involve some research on how to actually achieve this and decisions will need to be made on architecture. Could be worth investigating https://github.com/epics-containers and seeing what other facilities are using - there were plenty of talks at the last epics collab meeting.

Docker layers could be another approach we could investigate ie. having a docker layer (and image?) associated with each support module an IOC depends on ie. stream device, asyn etc. - this might be beneficial as we can then cache built versions of support modules

out of scope for this ticket:
- serial communication
- migrating every IOC
- container orchestration (starting/stopping containers)
- alarm server, archiving from a containerised IOC
- publishing things to github container registry/harbor.stfc.ac.uk unless it's required for a test workflow

### Acceptance criteria
- [ ] IOC tests pass against a containerised IOC
- [ ] Any decisions on architecture are documented on the developers manual
- [ ] subsequent tickets are created for things out of scope of this ticket and containerising other IOCs