Minor cleanup of creation of simulated convolved MD workspace.

Refs #8416
Foreground model now assumes input Q is in the lab frame, not sample.

Refs #8416
ResolutionModel now expects input coords in cartesian crystal frame.

This is the default output of ConvertToMD. Internally it rotates
to/from lab frame to perform the resolution calculation.
Refs #8416
Add a quantification model that simply returns a Q coordinate.

Used mainly for debugging transformations.
Refs #8416
Default to overwrite existing workspace in simulation.

Refs #8416
Add unity option to QCoordinate.

Refs #8416
Correct property count in test.

Refs #8416
Fix const-correctness in MDHistWorkspace.

Refs #8416
Fix normalization by events in MDHistWorkspaceIterator.

It had not been implemented at all when the events field was added
to the MDHistoWorkspace!
Refs #8416
Fix bounding box of cached detector to taking into account grouping.

Refs #8416
Fix CachedExperimentInfoTest

Refs #8416
Merge remote-tracking branch 'origin/bugfix/8416_quantification_fg_only'