Unify the flat/normal behavior of PC3 Button/ToolButton backgrounds

Noah Davisrequested to merge
work/ndavis/pc3-buttonhoverfocus into master

Rather than duplicating the behaviors in both Button.qml and ToolButton.qml, leading to bugs and inconsistencies, the Button/ToolButton background code is split into separate reusable files. The correct background is used depending on whether or not flat mode is enabled.

cc: @teams/vdg

Edited by Noah Davis

Merge request reports