Spec for removing tenant-id from api resource uri

Patch 2:
  Added examples for couple additional use cases where
  the API could be called by an admin user on behalf of
  another user.
  Fixed spec based on previous review comments

Patch 3:
  Added a work item for policy change

Patch 4:
  Removed the special admin use cases based on review
  comments.
  Made text corrections based on feedback
  Update the work items and backward compatibility logic

Patch 5:
  Cleaned up formatting/work-items
  Changed X-Tenant-Id to X-Project-Id

Patch 6:
  More formatting fixes

Patch 7:
  Removed Backward Compatibility support
  Changed spec name to match blueprint

Patch 8:
  Replaced all occurences of tenant-id with project-id
  Fixed wording errors based on review comments

Patch 9:
  Included client changes as another work item

Change-Id: I76a5e80288aed42d2b73839a2132f6c3e2cbb3dd
Blueprint: https://blueprints.launchpad.net/barbican/+spec/api-remove-uri-tenant-id
Merge "Spec for removing tenant-id from api resource uri"