So far, we used StorageManager to indicate a manager of all storage types as well as a handler of each storage type.
TAJO-1603 separates StorageManager to TableSpaceManager and StorageManager and its descendants.
This patch renames StorageManager to TableSpace. As a result, we will have the following relationships:
- TableSpaceManager plays a manager role for all storage types.
- TableSpace handles a specific storage type and a specific path on the storage type.