(POOLER-70) Add config for VM Provider

This commit adds a public function to access the internal variable holding the
VMPooler configuration.  This is required for later commits for the execute!
function testing.

lib/vmpooler/pool_manager.rb

@@ -19,6 +19,10 @@ module Vmpooler
       $threads = {}
     end
 
+    def config
+      $config
+    end
+
     # Check the state of a VM
     def check_pending_vm(vm, pool, timeout, provider)
       Thread.new do