Show team and repo badges on README

This patch adds the team's and repository's badges to the README file.
The motivation behind this is to communicate the project status and
features at first glance.

For more information about this effort, please read this email thread:

http://lists.openstack.org/pipermail/openstack-dev/2016-October/105562.html

To see an example of how this would look like check:

https://gist.github.com/24ea4c4972e293d584f2516466374da4

Change-Id: Ia1a92a9892cbb68f2adb5bad23b212ef2f329bb6

README.md

@@ -1,3 +1,10 @@
+Team and repository tags
+========================
+
+[![Team and repository tags](http://governance.openstack.org/badges/puppet-nova.svg)](http://governance.openstack.org/reference/tags/index.html)
+
+<!-- Change things from this point on -->
+
 nova
 ====