Three interrelated issues:
1) Implement an undo/redo type for renames so that we know to delete
the old lib entry and add a new lib entry
2) When doing so (for the undo/redo OR the original edit), we must
make a copy of the 'original' LIB_PART which is used for revert, and
hand it to the new lib entry
3) When comparing a modified component tree item with the current item
we must also check for aliases.
Fixes: lp:1743857
* https://bugs.launchpad.net/kicad/+bug/1743857
Fixes: lp:1744371
* https://bugs.launchpad.net/kicad/+bug/1744371
Fixes: lp:1744373
* https://bugs.launchpad.net/kicad/+bug/1744373