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