Add "list Glance API versions" test

Many projects provides multiple API versions and the version
information is very important for users, because users can know
what features are available on clouds. However, Tempest didn't
test the Clance API versions in long-term. So this patch adds
the corresponding test.

Change-Id: Ib85819fb71f0b12b64351b307d83a3beb77d7fad
diff --git a/releasenotes/notes/add-list-glance-api-versions-ec5fc8081fc8a0ae.yaml b/releasenotes/notes/add-list-glance-api-versions-ec5fc8081fc8a0ae.yaml
new file mode 100644
index 0000000..acc7a41
--- /dev/null
+++ b/releasenotes/notes/add-list-glance-api-versions-ec5fc8081fc8a0ae.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Add versions_client module for image service.
+    This new module provides list_versions() method which shows API versions
+    from Image service.