qt,cpp: Implement adding ADSKs to existing keys
* lang/cpp/src/context.cpp: Add functions for adding ADSKs. * lang/cpp/src/context.h: Ditto. * lang/qt/src/qgpgmequickjob.cpp: Add implementation of ADSK job. * lang/qt/src/qgpgmequickjob.h: Ditto. * lang/qt/src/quickjob.h: Add job for adding ADSKs.