CCRs: display diagnostic data from compressors

As a cryogenics support person, I would like to be able to monitor the diagnostic data reported by compressors connected to CCRs on various beamlines.

Currently, we do not talk to the compressors on most beamlines. Having the diagnostic data available would reduce the diagnosis time for cryogenics problems during cycle. Cryogenics have mentioned two models of compressor they are interested in:
- Sumitomo
- Cryomech

These compressors apparently do have a serial interface, but it is not usually in use at the moment.

Acceptance criteria:
- Meeting with cryogenics group held to make sure we have captured all requirements and models of compressor which they would like us to support. Ensure this meeting is written up and the minutes placed somewhere accessible.
- Appropriate tickets created for implementing any compressors we don't already have support for

Notes:
- There are some compressors involved in HiFi's cryomagnet, we should check whether they are the same make & model as some of the others we're being asked to control
- Cryogenics are initially interested in read-only monitoring of diagnostic data from the compressors, not control
- Cryogenics contact: Chris L