Add serial/batch fitting to GSAS-II tab of Engineering UI

[RichardWaiteSTFC]

Is your feature request related to a problem? Please describe.
EXNGIN-X scientists want serial/batch fitting in GSAS-II tab - this would allow a PAwley refiement to be performed for multiple files (each independently).

Describe the solution you'd like
User could supply list of focussed files
UI would loop over the files and run GSAS-II

UI would need some more options to:

• allow user to select which run to plot results of (by default show last run maybe?)
• Collate lattice parameters (and other fit parameters) in table so users can see how changing

[RichardWaiteSTFC]

Duplicate of #39606 which has more detail