Update docs building

Update docs building:
* Switch to sphinx-build
* Update requirements for Sphinx and openstackdocstheme for
  python 3
* Remove unneeded doc and translation sections from setup.cfg
* Remove install_command, it's unneeded, the default is fine.

Change-Id: I3d2e0459ba4aedf21c01d7725fe5ab266f9f4da3

setup.cfg

@@ -20,29 +20,6 @@ classifier =
 packages =
     zun_tempest_plugin
 
-[build_sphinx]
-all-files = 1
-warning-is-error = 1
-source-dir = doc/source
-build-dir = doc/build
-
-[upload_sphinx]
-upload-dir = doc/build/html
-
-[compile_catalog]
-directory = zun_tempest_plugin/locale
-domain = zun_tempest_plugin
-
-[update_catalog]
-domain = zun_tempest_plugin
-output_dir = zun_tempest_plugin/locale
-input_file = zun_tempest_plugin/locale/zun_tempest_plugin.pot
-
-[extract_messages]
-keywords = _ gettext ngettext l_ lazy_gettext
-mapping_file = babel.cfg
-output_file = zun_tempest_plugin/locale/zun_tempest_plugin.pot
-
 [entry_points]
 tempest.test_plugins =
     zun_tests = zun_tempest_plugin.tests.tempest.plugin:ZunTempestPlugin

test-requirements.txt

@@ -4,8 +4,8 @@
 
 hacking<0.13,>=0.12.0 # Apache-2.0
 
-sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2  # BSD
-openstackdocstheme>=1.20.0 # Apache-2.0
+sphinx>=2.0.0,!=2.1.0 # BSD
+openstackdocstheme>=2.0.0 # Apache-2.0
 # releasenotes
 reno>=2.5.0 # Apache-2.0
 doc8>=0.6.0 # Apache-2.0

tox.ini

@@ -7,12 +7,11 @@ ignore_basepython_conflict = True
 [testenv]
 basepython = python3
 usedevelop = True
-install_command = pip install {opts} {packages}
 setenv =
    VIRTUAL_ENV={envdir}
    PYTHONWARNINGS=default::DeprecationWarning
 deps =
-    -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
     -r{toxinidir}/test-requirements.txt
 commands = python setup.py test --slowest --testr-args='{posargs}'
 
@@ -28,7 +27,7 @@ commands = python setup.py test --coverage --testr-args='{posargs}'
 [testenv:docs]
 commands =
     doc8 --ignore D000 -e .rst doc/source/ CONTRIBUTING.rst HACKING.rst README.rst
-    python setup.py build_sphinx
+    sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:releasenotes]
 commands =