Walrus to Walrus+OSG upgrade

-Setup blockstorage system account
-Copy metadata for buckets from Walrus to OSG
-Copy metadata for objects from Walrus to OSG
-Modify Walrus buckets
-Modify Walrus objects
-Flush Walrus image cache

Implements EUCA-8595, EUCA-8872, EUCA-8873, EUCA-8596, EUCA-8874, EUCA-9145, EUCA-8871