Added hotkey for cycling through net & netclass color modes.
Added hotkey for cycling through ratsnest layer visibilities.
Added code to display hotkey (if set) on the above and on high-contrast
cycle.
Fixes https://gitlab.com/kicad/code/kicad/issues/9312
Note that the dialogs which have mutliple options were not moved over
as it seems perahps not the right choice to have them save state between
sessions.
Fixes https://gitlab.com/kicad/code/kicad/issues/8762
ADDED Paste Special... action in pcbnew
CHANGED Additional options for Paste Special... in eeschema, including
"Assign unique reference designators to pasted instance"