HGTD In AtlasDetectorID and Initialization of Standalone HGTD Identifier Dictionary
This MR updates the ID helper base class AtlasDetectorID
for HGTD to be standalone (previously under LAr) and adds a preliminary version of an HGTD identifier dictionary.
The LAr HGTD implementation is still left in place for now to cause less disruption (!35563 (merged)).
Edited by David Richard Shope