kconfig: qconf: use default platform shortcuts

kconfig: qconf: use default platform shortcuts

This renames "Load" to "Open" and switches Ctrl-L to Ctrl-O for the default
platforms. This may break the workflow for those used to it, but will make it
actually work for everyone else like me who would just expect the default
behavior. Add some more standard shortcuts where available. If they replace
the existing shortcuts they would have the same value in my case.

Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>