Switch to openstackdocstheme 2.2.1 and reno 3.1.0 versions. Using
these versions will allow especially:
* Linking from HTML to PDF document
* Allow parallel building of documents
* Fix some rendering problems

Update Sphinx version as well.

openstackdocstheme renames some variables, so follow the renames
before the next release removes them. A couple of variables are also
not needed anymore, remove them.

Set openstackdocs_auto_name to use 'project' as name.

Change pygments_style to 'native' since old theme version always used
'native' and the theme now respects the setting and using 'sphinx' can
lead to some strange rendering.

Depends-On: https://review.opendev.org/729744
Change-Id: Id3989cabdbf2204821531b00149aa0f1cb8a4955

OpenStack is dropping the py2.7 support in ussuri cycle.

Make a few cleanups:
- Remove python 2.7 stanza from setup.py
- Add python-requires to setup.cfg so that pypi and pip know
  about support Python version
- Remove ancient sections from setup.cfg
- Remove version_info setting from conf.py, openstackdocstheme does this
  automatically nowadays.

Change-Id: I5b9c159752c932f874015f20822862c70562c2bd

The help page for network auto allocated topology had a link to a
newton-era networking guide document that has been superseded and is
now maintained in the neutron repository.

This commit adds 'neutron' to the openstackdocstheme configuration so
that the :neutron-doc: role works, and updates the link to point to the
modern version therein.

Change-Id: I5bcb40e265b22f15ff2f5ca4936160e231bb4075

Sphinx errors have been fixed in the plugin projects for octavia, rsd,
trove, watcher, and zun, so we can now use autoprogram-cliff to generate
the docs for those.

Change-Id: Ia7790c5e86957afd0aec8f9a04ffc7aa968b4eeb
Story: #1735016
Task: #37241

We would like to use autoprogram-cliff to generate full docs inline for
each plugin. But for the following projects, that breaks the build:

- octavia
- rsd
- trove
- watcher
- zun

For those projects, we're using list-plugins instead, because that
builds, and it's better than nothing; but it only provides summaries of
the commands.

So with this commit, we add a link to the plugin documentation from the
actual plugin project where such documentation exists, which currently
is just:

- octavia
- watcher
- zun

(For rsd, I couldn't find openstack-published docs at all; for trove,
published docs exist, but the osc plugin isn't documented.)

Change-Id: I7c826ecef4319bead239e11b5f975302b2f24d1b
Story: #1735016
Task: #37244

This fixes the docs bug link generation for the normal docs
and release notes docs.

The requirement on openstackdocstheme is bumped to 1.23.2 to
pick up fix I2ed164b9b0badade702c50543ac1a5eea4d1867b.

Change-Id: I89711a391ee0fb7e40c1fbf83f950e2b582358d9
Story: #2005467
Task: #30546

This fixes local building of the documentation using tox, and allows the
gate to stop relying on pbr and move completely to the new docs PTI.

http://lists.openstack.org/pipermail/openstack-dev/2018-March/128594.html

Change-Id: I485acda07098a435753e91c1ca45e586de199c35

Change-Id: I832eade2ddab754664e5f57b9764e524e655e616

Change-Id: I413a6d059f4eb751ca5c8b5a9b61740ac93680b1

'cliff', the command line library used by 'osc_lib' (and, thus,
'python-openstackclient') recently gained a Sphinx extension to
automatically document cliff commands. This allows us to use the
documentation we already have in code instead of duplicating it in the
documentation.

Introduce the use of this, starting with the 'server' commands. This
requires extending the descriptions for two commands to ensure no
information is lost.

Change-Id: If701af8d5a3f78f4b173ceb476dd0c163be4b6ca