Add Goal in BaseStrategy + Goal API reads from DB

In this changeset, I changed the Strategy base class to add new
abstract class methods. I also added an abstract strategy class
per Goal type (dummy, server consolidation, thermal optimization).

This changeset also includes an update of the /goals Watcher API
endpoint to now use the new Goal model (DB entries) instead of
reading from the configuration file.

Partially Implements: blueprint get-goal-from-strategy
Change-Id: Iecfed58c72f3f9df4e9d27e50a3a274a1fc0a75f

watcher_tempest_plugin/services/infra_optim/v1/json/client.py

@@ -234,7 +234,7 @@ class InfraOptimClientJSON(base.BaseInfraOptimClient):
     def show_goal(self, goal):
         """Gets a specific goal
 
-        :param goal: Name of the goal
+        :param goal: UUID or Name of the goal
         :return: Serialized goal as a dictionary
         """
         return self._show_request('/goals', goal)