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

Change-Id: I395ba4bd6b887213d9d96a3281aca1e31e88ecb7

setup.cfg

@@ -22,29 +22,6 @@ classifier =
 packages =
     congress_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 = congress_tempest_plugin/locale
-domain = congress_tempest_plugin
-
-[update_catalog]
-domain = congress_tempest_plugin
-output_dir = congress_tempest_plugin/locale
-input_file = congress_tempest_plugin/locale/congress_tempest_plugin.pot
-
-[extract_messages]
-keywords = _ gettext ngettext l_ lazy_gettext
-mapping_file = babel.cfg
-output_file = congress_tempest_plugin/locale/congress_tempest_plugin.pot
-
 [entry_points]
 tempest.test_plugins =
     congress_tests = congress_tempest_plugin.plugin:CongressTempestPlugin

test-requirements.txt

@@ -5,8 +5,8 @@
 hacking>=1.1.0,<1.2.0 # Apache-2.0
 
 coverage!=4.4,>=4.0 # 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

tox.ini

@@ -7,14 +7,15 @@ ignore_basepython_conflict = True
 [testenv]
 basepython = python3
 usedevelop = True
-install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt} {opts} {packages}
 setenv =
    VIRTUAL_ENV={envdir}
    PYTHONWARNINGS=default::DeprecationWarning
    OS_STDOUT_CAPTURE=1
    OS_STDERR_CAPTURE=1
    OS_TEST_TIMEOUT=60
-deps = -r{toxinidir}/test-requirements.txt
+deps =
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -r{toxinidir}/test-requirements.txt
 commands = stestr run {posargs}
 
 [testenv:pep8]
@@ -34,7 +35,7 @@ commands =
     coverage xml -o cover/coverage.xml
 
 [testenv:docs]
-commands = python setup.py build_sphinx
+commands = sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:releasenotes]
 commands =