After all I don't need all that stuff in the cmakeplugin, all i needed
is now bundled in debugginghelper.h/cpp

Allows removing getting the instance once.

And add a instance() method to it.

The Debugger, cmake and Qt4 plugin all need it. More refactoring to it
coming.

That is we don't default to debug_and_release. We check the qt version
that is used for building, and if that one is not using
debug_and_release, we don't neither.

Fixes issues with handling additional dots in the filename in many
places.

Task: 246390