Adds tests covering Swift's container quotas middleware

The execution of the tests is conditional to a setting declared
in the config file (container_quotas_available by default to True).

There are 3 tests:
 + User uploads an object smaller than the quota successfully
 + User fails to upload an object larger than the bytes quota
 + User fails to upload many objects that exceeds the count limit

Closes-Bug: 1225891
Change-Id: Id93f6c3628624f115a3c7a91de8a8e7894003f3f
Merge "Adds tests covering Swift's container quotas middleware"