Updates to the AceToken API

Rework of some mappings for the AceToken and Staging APIs when #102 (closed) is complete

NEW

• GET /api/bags/<bag_id>/files/<file_id>/token
• PUT /api/bags/<bag_id>/storage/<type>

UPDATE

• POST /api/bags/<bag_id>/tokens -> /api/bags/<bag_id>/files/<file_id>/token
• PUT /api/bags/<bag_id>/storage/<type> -> /api/bags/<bag_id>/storage/<type>/active

REMOVE

• PUT /api/bags/<bag_id>/storage/<type>/fixity
• GET /api/bags/<bag_id>/storage/<type>/fixity
• GET /api/bags/<bag_id>/storage/<type>/fixity/<alg>

Added stretch goal for batch ingestion of tokens:

• POST /api/bags/<bag_id>/tokens
  • Request body, responses, etc are tbd