Resolves unclear formatting of compute extensions documentation at
http://nova.openstack.org/api_ext/index.html
The rst extensions template has been updated to include extension name as
top level hierarchy, and demote all other content.
All existing documentation pages have been reformatted as per the updated
template.
The ext_aggreagates.rst file has also been added to index.rst.
Amendments:
- Author added to Authors file
- Typo in ext_volumes.rst fixed
Change-Id: Id67ef91a6e8eaaf4fba46abbd57759c77aaf8991
a68156c100