[ #60972 ] Port many calsses to use D-Pointer

src/call.h

src/callmodel.cpp

src/callmodel.h

src/contact.h

src/historymodel.h

src/imconversationmanager.cpp

src/imconversationmanager.h

src/instantmessagingmodel.h

src/itembackendmodel.cpp

src/itembackendmodel.h

src/lastusednumbermodel.cpp

src/lastusednumbermodel.h

src/legacyhistorybackend.h

src/numbercategory.cpp

src/numbercategory.h

src/numbercategorymodel.cpp

src/numbercategorymodel.h

src/phonenumber.h

src/presencestatusmodel.cpp

src/presencestatusmodel.h