Entity deletion should be possible via HBase admin operations

Avro schema version numbers are stored in a column called _s:sv_<entity-name> by ManagedSchemaEntityVersion. This means that for tables storing multiple entities the version information is in the _s column family, so deleting the version information for one entity (when deleting the entire entity) is not possible without a costly scan of the entire table. If the column family contained the entity name (e.g. _s_<entity-name>) then the column could be deleted using an admin operation.