Improve performance of peaks view in SliceViewer

[Peter Peterson]

The displaying of peaks has everything to do with just in time calculation of values for display in the peak workspace. Reduce the amount of information that is calculated.

Related to #7175.

[Peter Peterson]

Re #7205. Change the way column sizes are setup.

Since QTableView likes to look at all cells to calculate the width. Changed the hint for how to calculate column sizes to be "Interactive."

Changeset: e876ae16d8bf498282776f7cb2e44bcaca791877

[Peter Peterson]

Re #7205. Adding back in reasonable default values for column widths.

Changeset: 0dcde5e3c39160ec1cd188d3fe81e65fe83b16bb

[Peter Peterson]

This is on ​feature/7205_sliceview_performance.

The fix submitted takes care of performance issues because of the table of peaks being slow, but does nothing for the raster image being slow. That will be addressed in #7217.

To test:

1. generate a md-workspace (such as with the "SCD event reduction" interface)
2. LoadIsawPeaks the file attached to #7217.
3. Bring up the slice viewer and add the peaks workspace
4. Use the scrollbar to view more of the peaks workspace

Note: Things that change the view in the raster image will still be very slow and are not a subject of this ticket.

[Michael Reuter]

In the QPeaksTableModel::updateDataCache call, the peak intensity is added twice to the cache object. I think the last call should be for the peak sigma intensity.

[Peter Peterson]

Re #7205. Added the missing 5 characters to fix the bug.

Thanks for catching this one.

Changeset: b0fcb8dc5fe9bf35073697525d0f30359f163965

[Peter Peterson]

Same instructions for testing. Same branch too.

[Michael Reuter]

The table of peaks is very responsive now as long as the raster image is not touched.

[Stuart Campbell]

This ticket has been transferred to github issue ​8051