METReconstruction: First attempt at preparing the MET Reconstruction code for the run III configuration system

Move legacy run II configuration code into new subdirectory of python to avoid confusion. Create new file (METReconstruction/share/METRecConfig.py ) to allow standalone testing of the new configuration code. Additional cleanup to move initialisation of private ToolHandles into header files in METReconstruction package. Tier0 tests have been checked offline Next steps will involve further work on the new configuration system