Switch to newer openstackdocstheme version

Switch to openstackdocstheme 2.2.1 version. Using
this version will allow especially:
* Linking from HTML to PDF document
* Allow parallel building of documents
* Fix some rendering problems

Update Sphinx version as well.

Set openstackdocs_pdf_link to link to PDF file. Note that
the link to the published document only works on docs.openstack.org
where the PDF file is placed in the top-level html directory. The
site-preview places the PDF in a pdf directory.

Disable openstackdocs_auto_name to use 'project' variable 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.

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.

See also
http://lists.openstack.org/pipermail/openstack-discuss/2020-May/014971.html

Change-Id: Ie0575b318b044b750e86e1622cc3c470031f2cc6

doc/source/conf.py

@@ -35,7 +35,7 @@ extensions = ['sphinx.ext.autodoc',
              ]
 
 # Feed configuration for yasfb
-feed_base_url = 'http://specs.openstack.org/openstack/cloudkitty-specs'
+feed_base_url = 'https://specs.openstack.org/openstack/cloudkitty-specs'
 feed_author = 'OpenStack Cloudkitty Team'
 
 todo_include_todos = True
@@ -271,3 +271,9 @@ epub_copyright = u'2014, OpenStack Cloudkitty Team'
 
 # Allow duplicate toc entries.
 #epub_tocdup = True
+
+# -- Options for openstackdocstheme -------------------------------------------
+openstackdocs_repo_name = 'openstack/cloudkitty-specs'
+openstackdocs_auto_name = False
+openstackdocs_use_storyboard = True
+openstackdocs_pdf_link = True

requirements.txt

@@ -1,6 +1,6 @@
 pbr>=2.0
-sphinx>=1.6.2
+sphinx>=2.0.0,!=2.1.0 # BSD
 testrepository>=0.0.18
 testtools>=0.9.34
-openstackdocstheme>=1.32.1 # Apache-2.0
+openstackdocstheme>=2.2.1 # Apache-2.0
 sphinxcontrib-svg2pdfconverter>=0.1.0 # BSD