Add Tests for Groups Volume APIs - Part 1

This is the 1st patch that adds the tempest tests for generic
volume groups APIs in Cinder. It adds groups and group_types clients.
It tests the following group APIs:

  * create group
  * delete group
  * show group
  * list group

Change-Id: Id1779fe5dce50b062ca0ff841a7ede72cac9dd73
diff --git a/releasenotes/notes/add-volume-groups-tempest-tests-dd7b2abfe2b48427.yaml b/releasenotes/notes/add-volume-groups-tempest-tests-dd7b2abfe2b48427.yaml
new file mode 100644
index 0000000..898d366
--- /dev/null
+++ b/releasenotes/notes/add-volume-groups-tempest-tests-dd7b2abfe2b48427.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Add groups and group_types clients for the volume service as library.
+    Add tempest tests for create group, delete group, show group, and
+    list group volume APIs.