Spooling up a full PLAYER in the background takes too long.
This also fixes bugs around how the tables are saved, although
that was just missing code rather than anything architectural.
Fixes: lp:1785436
* https://bugs.launchpad.net/kicad/+bug/1785436
Unifies the different sections of hotkeys so that we are not storing two
[eeschema] or [pcbnew] sections in two different files.
Previous hotkey definitions are loaded at start if they exist but are
overwritten by the new format, if it exists. Changes to hotkeys save
only in the combined format.
Hotkey editor for each application only shows the hotkeys relevant to
that application.
Fixes: lp:1741757
* https://bugs.launchpad.net/kicad/+bug/1741757
Fixes: lp:1668799
* https://bugs.launchpad.net/kicad/+bug/1668799
Jeff Young
Seth Hillbrand
Wayne Stambaugh
jean-pierre charras