dolphin: convert kitemviews/ to qt5 signal slot syntax

dolphin: convert kitemviews/ to qt5 signal slot syntax

This conversion was performed automatically using convert2qt5signalslot.
The only manual changes required were changing the overloaded signal
KDirLister::redirection and KDirLister::completed from KUrl to QUrl. All
other cases were no problem since these signals are not overloaded and a
static_cast for disambiguation is not necessary.

Code inside HAVE_BALOO is not converted yet, will do that once I can build
a version with Baloo.