Should also partly replace the new QXmpp::SendError.
[x] IQ results should also use it instead of mixing received QXmppStanza::Errors with artificial QXmppStanza::Errors generated when some other, local error occurred.
[x] client
[x] e2ee extension
[x] replace SendError::Type with unit structs to avoid having matching of type and of enum value when handling send errors??
Should also partly replace the new
QXmpp::SendError.QXmppStanza::Errors with artificialQXmppStanza::Errors generated when some other, local error occurred.replaceSendError::Typewith unit structs to avoid having matching of type and of enum value when handling send errors??e2ee ext: merge NotEncrypted into QXmppError