Refactored Strategy selector to select from DB

In this changeset, I refactored the strategy selector to now
look into the Watcher DB instead of looking into the configuration
file.

Partially Implements: blueprint get-goal-from-strategy

Change-Id: I2bcb63542f6237f26796a3e5a781c8b62820cf6f

watcher_tempest_plugin/tests/scenario/test_execute_basic_optim.py

@@ -30,7 +30,7 @@ CONF = config.CONF
 class TestExecuteBasicStrategy(base.BaseInfraOptimScenarioTest):
     """Tests for action plans"""
 
-    BASIC_GOAL = "BASIC_CONSOLIDATION"
+    BASIC_GOAL = "SERVER_CONSOLIDATION"
 
     @classmethod
     def skip_checks(cls):