Adding support for orders and secrets.

-Updating PUT function
-Adding expiration and finding orders support
-Updating create and check order method to use configs
-Adding content types attribute support to secrets
-Fixing PEP8 issues

Change-Id: Ic7d29be22dff633c4bd8e52f9ede7dfbb0c1b337
Tenants API Client (Review).

 1. Added a tenants api client and related mocked tests.
 2. Moved all mocked tests to a metatests package.
 3. Fixed string formatting issues in tenants api client.
 4. Renamed tenant-api to tenant_api in the metatests package.
 5. Fixed issues as per reviewer comments.
 6. Fixed a bug in a user model for users-api.
 7. Refactored a tenant responses model for tenants-api.

Change-Id: I578867a4bcafb635fe9b38a3238385569ce2fe77
Merge "Tenants API Client (Review)."
Merge "Adding support for orders and secrets."