This updates the API root documentation, which was non-existent,
and the Node documentation significantly, replacing many of the samples
and adding more verbiage to each property.
It's not perfect, but this is vastly more correct than the current docs.
Change-Id: Iaeb1c80ac0655fc0d73fa495ed43e3c02b345495
Per this email[0], it's time to migrate our API docs into our tree.
This copies the sphinx extension from nova into our tree as well, which
will be later split into its own python module. At that time we can cut
over to the module and drop it from our tree.
The conf.py and the tox environment are also cribbed from nova.
[0] http://lists.openstack.org/pipermail/openstack-dev/2016-May/093765.html
Change-Id: I683cc4d6459d77c42951a06247b6f9ff8f8456bd
