Implement a ServerConfigBackendFactory

mostly to keep layers separated.

server/lib/python/cartodb_services/cartodb_services/refactor/backend/server_config.py

@@ -0,0 +1,13 @@
+from cartodb_services.refactor.storage.server_config import InDbServerConfigStorage
+
+
+class ServerConfigBackendFactory(object):
+    """
+    This class creates a backend to retrieve server configurations (implementing the ConfigBackendInterface).
+
+    At this moment it will always return an InDbServerConfigStorage, but nothing prevents from changing the
+    implementation. To something that reads from a file, memory or whatever. It is mostly there to keep
+    the layers separated.
+    """
+    def get(self):
+        return InDbServerConfigStorage()