Regression+: Resize/Rotate shortcut keys should be constrained by selected corner/side handle

Summary:

In the Selector Tool, when a corner/side handle is selected, resize/rotate shortcut keys (< , > / [ , ]) should have operations constrained to that "anchor". If the top left-handle is selected, the object will resize/rotate toward, away, or around from that corner.

Notes:

We used to have this functionality by hovering over handles before they were selectable. This is technically a regression (happened <1.0 from my brief testing). Filing as an RFE since Martin proposed this solution (and assigned to him per his request) since this cleaner implementation will be a massive usability improvement.

Version info

1.0> (last 1.0.x line appimage from inkscape.org was earliest tested)