* Switch to newer openstackdocstheme version and remove values that are
set now by openstackdocstheme.
* Remove py2 requirments for docs, we only build with python3.
* Update deps for docs building, we don't need the default.
* Remove modindex, this is not build, see
https://docs.openstack.org/ec2-api/latest/py-modindex.html
Change-Id: I6958cbed944de0a1eea02de10c5a4916b6a7293d
The api documentation is now published on docs.openstack.org instead
of developer.openstack.org. Update all links that are changed to the
new location.
Note that redirects will be set up as well but let's point now to the
new location.
For details, see:
http://lists.openstack.org/pipermail/openstack-discuss/2019-July/007828.html
Change-Id: Ib3f8664195986bae45123061cd2afc816c6403d8