Extract ETP client code in a library

The actual code contains a C++ ETP client embedded directly inside the oes_eml library.

This request has two purposes:

1. Extract that code into a separate shared library with less dependency so that it will be easier for anyone to build an ETP client application.

Right now the client code consists of 4 main files

• oes/eml/etp12/Client.hpp
• oes/eml/etp12/Client.cpp
• oes/eml/etp12/ImportEpc.cpp
• oes/eml/etp12/ExportEpc.cpp

2. New common library to allow the creation of the client library. The common library will contain code used from both eml and client libraries