split the controllers into separate files

owrx/controllers/metrics.py

@@ -0,0 +1,9 @@
+from . import Controller
+from owrx.metrics import Metrics
+import json
+
+
+class MetricsController(Controller):
+    def handle_request(self):
+        data = json.dumps(Metrics.getSharedInstance().getMetrics())
+        self.send_response(data, content_type="application/json")