Rename/relocate clouddns to match other providers

lib/vmpooler/dns/google/clouddns.rb

@@ -1,14 +1,16 @@
 # frozen_string_literal: true
 
-require_relative "clouddns/version"
+require 'googleauth'
+require 'google/cloud/dns'
 
 module Vmpooler
-  module Dns
-    module Google
-      module Clouddns
-        class Error < StandardError; end
+  class PoolManager
+    class Dns
+      class Google
+        class Clouddns
           # Your code goes here...
         end
       end
     end
   end
+end