qt: Extend SignKeyJob to create trust signatures
* lang/qt/src/signkeyjob.h (SignKeyJob::setTrustSignature): New. * lang/qt/src/qgpgmesignkeyjob.h, lang/qt/src/qgpgmesignkeyjob.cpp (QGpgMESignKeyJob::setTrustSignature): New. * lang/qt/src/qgpgmesignkeyjob.cpp (sign_key): Handle trust signatures. (QGpgMESignKeyJob::start): Pass trust signature attributes to sign_key. (QGpgMESignKeyJob::setTrustSignature): New.
This allows Kleopatra to create trust signatures for trusted
introducers.