Define volume quotas_client as library

Volume quotas_clients have good interfaces now,
then this patch makes them as a library.

Partially implements blueprint consistent-service-method-names

Change-Id: I91c4ac55680604143a4599e136d9d673bbb27e24
diff --git a/releasenotes/notes/volume-clients-as-library-9a3444dd63c134b3.yaml b/releasenotes/notes/volume-clients-as-library-9a3444dd63c134b3.yaml
index 6a4fc2b..cf504ad 100644
--- a/releasenotes/notes/volume-clients-as-library-9a3444dd63c134b3.yaml
+++ b/releasenotes/notes/volume-clients-as-library-9a3444dd63c134b3.yaml
@@ -12,5 +12,7 @@
       * extensions_client(v2)
       * hosts_client(v1)
       * hosts_client(v2)
+      * quotas_client(v1)
+      * quotas_client(v2)
       * services_client(v1)
       * services_client(v2)