CaloDetMgrDetDescrCnv code cleanup

Migrated CaloMgrDetDescrCnv to AthMessaging, and made a number of cosmetic and stylistic changes in CaloMgrDetDescrCnv.cxx.

Dropped two obsolete python scripts:

• CaloDetMgrDetDescrCnv/python/CaloDetMgrDDCnv.py
• CaloDetMgrDetDescrCnv/share/CaloTTDetMgrDetDescrCnv_joboptions.py

and updated their clients.

Fixed broken TestLArDetDescr/share/TestCaloDDE_jobOptions.py