Add V3 API samples for quota-sets/class-sets,inst-usage-audit-log

Partially implements blueprint v3-api-unittests

Change-Id: I6c21e5dffc5669bb6ab2bba091b97725cc19fd69
Add metafiles for quota-sets/classes,instance-usage-audit-log

Converts quota-sets, quota-classes, instance-usage-audit-log
api sample to create meta files for api sample docs.
We use this to auto generate the specification document

Change-Id: Ib5f4b64281db6a17914a97da3cdab930e6276bd5
Merge pull request #7 from soulxu/add_metafile_quota_sets

Add metafiles for quota-sets/classes,instance-usage-audit-log