109 list vault

1. list all vaults (in the project_id).  
2. return dicts of vaultnames and their urls, structure is listed in tests/test_vault_controller.py

TODO: need return vault status heads.


We can still use 412 and just ensure that Swift driver returns 409.
What happens if we have another backend that uses 409? Or swift returns 409 instead?
This is our API contract.

Also, I did this in PR #64.