Analytics: changing default separator for smoothing plugin

- Using a hash ("#") in MQTT topics apparently crashes the mosquitto client

analytics/operators/smoothing/SmoothingOperator.cpp

@@ -28,7 +28,7 @@
 #include "SmoothingOperator.h"
 
 SmoothingOperator::SmoothingOperator(const std::string& name) : OperatorTemplate(name) {
-    _separator = "#";
+    _separator = "-";
     _exclude = "";
     _updateMetadata = true;
 }