This unifies everything under a single architecture with a "don't
show again" dialog. Since everything now goes through the same
path it should be reasonably easy to make it do whatever we want
in the future.
Right now it presents 3 options: modify only unlocked items, override
locks and modify all items, or cancel command.
Fixes a few commit issues based on the std:: rework. Add an option to
delete tracks fully in pads and makes merge tracks smarter
Fixes: lp:1787190
* https://bugs.launchpad.net/kicad/+bug/1787190
Jeff Young
Simon Richter
Seth Hillbrand