Rename service to transport

Change-Id: Ic875f2c67147b0e53ae3c3ec1cebe6ef288cbd3d
Refactorize transports to make then pluggable

Change-Id: I5f24f4a56393ea45d537e241b610d40f77037d6a
Improve transport factory

Change-Id: I8a25bb28c709f89ab0031621a3ce471615db2dd1