Merge branch 'feature/8455_correct_sample_geom_cor' into feature/8444_multiperiod_data
re #8444: Allow reduction of multiperiod data
re #8438: Correct on_load_sample method.
re #8444: Rename variable wksp_name
re #8444: Revise LoadRun and LoadSample to support group workspace
re #8444: Do not use protected attribute _period outside LoadRun

Improve the way we get the period name
re #8444: Move check outside LoadSample

LoadSample itself should not care about this. This will allow the creation
of the tests on the load as well.
re #8444: Support multiperiod reduction
re #8444: Correct the usage of period in the output name

The output name should show period only if the workspace has many periods
or if the user defined which period to run.
re #8444: Ensure that suffix is correctly applied
re #8444: LoadRun corrections

1 - It corrects the access to multiperiod data. It uses the _index_of_group
and not _period which is not changed internally by LoadRun (keeps memory
of the way it was initialised)
2 - It corrects the wrong assumpition that the datafile will have the
runnumber correctly placed. It asks the workspace its runnumber.
Merge branch 'feature/8444_multiperiod_data' into develop