Add Voluptuous to validate the action parameters

We want a simplest way to validate the input parameters of an
Action through a schema.

APIImpact
DocImpact
Partially implements: blueprint watcher-add-actions-via-conf

Change-Id: I139775f467fe7778c7354b0cfacf796fc27ffcb2

requirements.txt

@@ -17,6 +17,7 @@ oslo.utils>=3.4.0   # Apache-2.0
 PasteDeploy>=1.5.0
 pbr>=1.6
 pecan>=1.0.0
+voluptuous>=0.8.6 # BSD License
 python-ceilometerclient>=2.2.1
 python-cinderclient>=1.3.1
 python-glanceclient>=1.2.0