The accelerator strings really shouldn't be part of the translation,
and some translations have cause the accelerator keys to be incorrectly
handled. It is simpler to make it separate and just join them to the
translated string.
Make all accelerator modifiers use lowercased Ctrl instead of CTRL
to be the same as the other modifiers.
Fixes https://gitlab.com/kicad/code/kicad/issues/5992
Ian McInerney
Wayne Stambaugh
Jeff Young