Switch to openstackdocs theme

This patch updates the docs for the security role to use the
openstackdocs theme and adds doc8 linting. This matches up with
OpenStack-Ansible's docs changes.

Change-Id: Ie8265bdaf8f8b91454766f5beba14645aabf77cc

tox.ini

@@ -37,9 +37,21 @@ setenv =
 
 [testenv:docs]
 commands=
+    bash -c "rm -rf doc/build"
+    doc8 doc
     python setup.py build_sphinx
 
 
+[doc8]
+# Settings for doc8:
+extensions = .rst
+# Disable some doc8 checks:
+# D000: Check RST validity
+# D001 Line too long
+# D002 Trailing whitespace
+ignore = D000,D001,D002
+
+
 # environment used by the -infra templated docs job
 [testenv:venv]
 deps = -r{toxinidir}/test-requirements.txt