New ECAL Unpacker code , off in sequences for the time being

New Ecalunpacker module from Philippe Gras. Not used in standard sequences for this PR. We plan to activate it at a later time.
I would advice to use `std::chrono::high_resolution_clock` or `std::chrono::steady_clock` : on my laptop they are as fast as `getimeofday`, and ~50 times more accurate.