IOC: MSH150 Collimator improvements

As a developer I would like the MSH150 collimator to be more like an IBEX IOC; however this is not a core piece of equipment and may not be used again so do these before next use if needed.

These are issues from a review:

1. add .gitattributes
1. add LICENCE FILE
1. IOC should be moved into IOCs not support module. (update RELEASE to capture this change)
1. add interesting PVs
1. add archive PVs
1. add alarm PV
1. add emulator, alarm and tests.
1. Update documentation at
1. Add OPI

I have not been able to run this but it did run against the device.

Started in #3398

Start by reviewing the existing MSH150 IOC and the changes begun in #3398. Check the support module, RELEASE, documentation, OPI, and any existing emulator, alarm, or test entry points; the review list also calls for .gitattributes, a licence file, interesting and archive PVs, and an alarm PV. Done means the requested IOC, configuration, documentation, OPI, emulator, alarms, and tests are implemented and the IOC runs against the device.

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