22.0-cleanup-InDetIdentifier

This only affects the SCT_ID class:

• Remove non functioning test_indet_id executable and updated CMake to reflect this
• Introduce a localMessage function to replace the 'if msgSvc .... else cout<<' style of messaging (should continue to work with or without Gaudi initialised)
• Remove all redundant in-class checking now that we have unit tests
• Change internal representation of the vector of IdentifierHashes to be vector<IdentifierHash> (was vector<short unsigned int>
• Use the IdentifierHash default c'tor (which produces an invalid IdentifierHash) for undefined hash values instead of the home-grown value of 64000

Unit tests confirmed to be ok; updated error message with white-space changes to be compatible with new error message format.