Groundwork for adaptation of Muon Geometry to the newDD model. This is the...

These changes are towards an evolution of the detector description code, enabling detectors to restore geometry from a single input file rather than building it within Athena.

They will not alter any output, it is preparatory work.

It is the first of a two related MR's; the next will come after successful merge.

In more detail:

Groundwork for adaptation of Muon Geometry to the newDD model. This is the first of two MRs and should not be disruptive. Friendship to MuonChamberLite is added in four Readout Geometry classes. Friendship in C++ is not good but follows the model left by the muon community and so will not be disruptive. A print statement was corrected in RpcReadoutElement. CMakeLists was prepared for the upcoming MR which uses extra libraries. MYSQL was stripped of no-longer-required vestiges. Much more of that stripping should still be performed as a general cleanup of this code is to be desired.