CMakeParseJob: Hack to get rid off the dead-lock

Aleix is going to have a look at it
Add CMake::commandsFile

This is for retrieving the file path of the 'compile_commands.json' file
Minor: Add missing copyright
#include <KLocale> -> <KLocalizedString>
Remove includes to KGlobal

They were never needed anyway
CMake: Make JSON import threaded

Before this patch parsing the compile_commands.json file blocked the
main thread. Make the parsing async instead.

REVIEW: 120164
port KStandardDirs -> QStandardPaths
fix warning
fix compilation on jenkins, couldn't reproduce here, for some reason
Fix build.

Was missing a KDebug include.