swarm: add ability to answer to a message

bin/dbus/cx.ring.Ring.ConfigurationManager.xml

bin/dbus/dbusconfigurationmanager.cpp

bin/dbus/dbusconfigurationmanager.h

bin/jni/conversation.i

bin/jni/datatransfer.i

bin/nodejs/conversation.i

src/client/conversation_interface.cpp

src/client/datatransfer.cpp

src/jami/conversation_interface.h

src/jami/datatransfer_interface.h

src/jamidht/conversation.cpp

src/jamidht/conversation.h

src/jamidht/conversation_module.cpp

src/jamidht/conversation_module.h

src/jamidht/jamiaccount.cpp

src/jamidht/jamiaccount.h

test/unitTest/conversation/conversation.cpp