qt: Add job for quick commands
* lang/qt/src/qgpgmequickjob.cpp, lang/qt/src/qgpgmequickjob.h, lang/qt/src/quickjob.h: New. * lang/qt/src/Makefile.am, lang/qt/src/protocol.h, lang/qt/src/protocol_p.h, lang/qt/src/job.cpp: Update accordingly.
Keeping it in line with the Job for everything pattern.
Although it's reduced to one job for four commands as
the commands all behave the same.