Clean-up of api-site - make sure all extensions are included with code samples

Closes-Bug: #1236921

Change-Id: Ifd645fa58d6c7f92d1fcc029095e914e08c66d15
author: diane fleming
Merge "Clean-up of api-site - make sure all extensions are included with code samples"
Add "used limits for admins" extension
Added missing files that broke the build (my fault)
Refreshed api_samples from nova code base

Closes-Bug: #1195570

Change-Id: Ieb18a90d58a2b845e5c8251968184f221bf4eb45
author: diane fleming