Refactor d3 Test Run scatter plot code to provide better UX. namely:

- Better visual feedback on selected / hovered test run plots which
adapt to zooming.
    - Radius increase on Mouseover graph plot circles is proportional to
# Test Results being rendered
    - Visual indicators for compare selection.

- Added ctrl+click handling for test run plots to implemet selection for
compare
- Added right-click context menu for compare
- Added new skeleton views for Test Suite Compare View.