new: Added documentation for the object-storage/buckets endpoints (#121)

* new: Added documentation for the object-storage/buckets endpoints

This is a draft; please review carefully and do not merge without
populating placeholder links.

These endpoints have existed for some time, but are finally being
documented (the last two are shipping on Monday).  I _do not_ advise
actual users to use these endpoints; they're mostly for the benefit for
cloud.  In keeping with API philosophy, they _are_ available to all
customers, but the s3 API will almost certainly be more useful in all
cases, which is why using these endpoints is discouraged.

* updated to add curl, links to ceph, and minor copy edits

* Copy Edits and link updates.

Add missing query parameter for Get Object Storage Bucket Contents
Add required to various endpoint properties.

* Update GET endpoint summaries to follow List, View convention

* added content-type json to curl samples

* small copy edit change for spacing

Author: Dorthu