Switch to newer openstackdocstheme and reno versions

Switch to openstackdocstheme 2.2.0 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. A
couple of variables are also not needed anymore, remove them.

Depends-On: https://review.opendev.org/728938
Change-Id: I072cf215486d672eacd3a57483cb2b311483c844

doc/requirements.txt

@@ -1,8 +1,8 @@
 # The order of packages is significant, because pip processes them in the order
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
-openstackdocstheme>=1.20.0 # Apache-2.0
-sphinx>=1.8.0,!=2.1.0 # BSD
+openstackdocstheme>=2.2.0 # Apache-2.0
+sphinx>=2.0.0,!=2.1.0 # BSD
 doc8>=0.6.0 # Apache-2.0
-reno>=2.5.0 # Apache-2.0
+reno>=3.1.0 # Apache-2.0
 sphinxcontrib-apidoc>=0.2.0  # BSD

doc/source/conf.py

@@ -23,15 +23,14 @@ extensions = [
     'stevedore.sphinxext'
 ]
 # openstackdocstheme options
-repository_name = 'openstack/oslo.db'
-bug_project = 'oslo.db'
-bug_tag = ''
+openstackdocs_repo_name = 'openstack/oslo.db'
+openstackdocs_bug_project = 'oslo.db'
+openstackdocs_bug_tag = ''
 
 # The master toctree document.
 master_doc = 'index'
 
 # General information about the project.
-project = u'oslo.db'
 copyright = u'2014, OpenStack Foundation'
 
 # If true, '()' will be appended to :func: etc. cross-reference text.

releasenotes/source/conf.py

@@ -42,9 +42,9 @@ extensions = [
     'reno.sphinxext',
 ]
 # openstackdocstheme options
-repository_name = 'openstack/oslo.db'
-bug_project = 'oslo.db'
-bug_tag = ''
+openstackdocs_repo_name = 'openstack/oslo.db'
+openstackdocs_bug_project = 'oslo.db'
+openstackdocs_bug_tag = ''
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']