Add reno to tempest

Tempest is going to be on pypi and expose a stable interface in
the tempest.lib namespace, so adding reno to it.

Partially-implements: bp tempest-lib-reintegration
Change-Id: Ice4c27f7bc6d0154cfced9789f3c82236106a9e3
diff --git a/releasenotes/source/index.rst b/releasenotes/source/index.rst
new file mode 100644
index 0000000..584540b
--- /dev/null
+++ b/releasenotes/source/index.rst
@@ -0,0 +1,14 @@
+===========================
+ tempest Release Notes
+===========================
+
+ .. toctree::
+    :maxdepth: 1
+
+    unreleased
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`search`