Re #7099. Adding all of the columns into the peak table.
Re #7099. MORE COLUMNS!!!!!!!! in peaks table of slice viewer.
Re #7099. Added tech for introspection and turning off columns.

It checks for RectagularDetectors, technique, and the facility.
Re #7099. Adding hiding and showing columns to PeaksWorkspaceWidget.

This a step towards having the visible columns settable.
Re #7099. qtdesigner's default dialog box.
Re #7099. Moved files into their proper homes.
Re #7099. Renamed PeaksViewerOptionsDialog to PeaksViewerOverlayDialog
Re #7099. Got the optional columns dialog working.
Re #7099. Changed name of existing options dialog box.
Re #7099. Adding the peaks column dialog to PeaksViewer.

I love working towards encapsulation.
Re #7099. Add in the rest of the plumbing for optional columns

...in the peaks table of slice viewer.
Merge remote-tracking branch 'origin/feature/7099_peaks_table_improvements'