[v8r6] Improvements of RAWIntegrityAgent

Quite some changes. Next step is SQLAlchemy

• Use the bulk removal instead of sequential in the xmlrpc call of DataMover

• Remove useless methods. Don't call again checkArgumentFormat

• reformat RAWIntegrityAgent to perform direct delete

• Does not use anymore this non existing retransfer call

• Does not try to remove from Destination anymore

• Performs bulk removal and registrations

• Does not create requests anymore, but delete directly

• Uses intermediate states in case of errors (Copied, Migrated)

• Correct documentation