add ATLAS_NOT_THREAD_SAFE to unsafe mdt calibration code classes

Hi,

there are several classes in the MDT calibration code which are used to e.g. make calibration ntuples from the calibration stream or to run calibration algs on those ntuples. Those will most likely never be executed in multiple threads. This MR explicitly adds the ATLAS_NOT_THREAD_SAFE to classes which are clearly not thread safe to avoid misleading false positive thread safety warning arising from them.

Best, Nico