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/api/admin/test_audit_template.py

@@ -137,7 +137,7 @@ class TestAuditTemplate(base.BaseInfraOptimTest):
         new_name = 'my at new name %s' % uuid.uuid4()
         new_description = 'my new at description'
         new_host_aggregate = 10
-        new_goal = 'BASIC_CONSOLIDATION'
+        new_goal = 'SERVER_CONSOLIDATION'
         new_extra = {'key1': 'new-value1', 'key2': 'new-value2'}
 
         patch = [{'path': '/name',