Adding GPhL workflow with some refactoring - Part 1
Created by: rhfogh
Goes with a similar PR for mxcube3.- which is merged as of 20210927
The GPhL part is still not mature for looking at, but I would greatly appreciate comments on the non-GPhL, refactoring parts.
Notably I have made a change so you can pass multiple paths for the xml configuration files path1:path2, as was always possible in mxcubecore. This significantly simplifies keeping a remote set of repositories that you might want to test with different beamline set-ups.