misc: cleanup trust request (replaced by conversation requests)

src/app/conversationsadapter.cpp

src/app/conversationsadapter.h

src/libclient/api/contactmodel.h

src/libclient/authority/daemon.cpp

src/libclient/authority/daemon.h

src/libclient/callbackshandler.cpp

src/libclient/callbackshandler.h

src/libclient/contactmodel.cpp

src/libclient/conversationmodel.cpp

src/libclient/qtwrapper/configurationmanager_wrap.h