Migrate Vates/Inelastic_Workflow to new API

re #7703
Migrate Inelastic/CommonFunctions to new api

re #7703
Migrate SliceViewerPythonInterfaceTest.py to new API

re #7703
Migrate MDEvents/scripts/mdevents_optimize.py to new api

re #7703
Migrate speed_vs_numevents.py to new api

re #7703
Migrate NormaliseToUnitTest.py to new api

re #7703
Migrate NormaliseToUnitTest.py to new api

re #7703
Remove the _getHeldObject from script in MDEvents

re #7703
Correct the syntax error doesExist

re #7703
Remove scripts that are not used anymore

These scripts were created when building MDEventWorkspace in order to profile
the options available. Now, they are not used anymore.

re #7703
Merge remote branch 'origin/feature/7703_new_api'