Resolve "To improve the device watching mechanism a fetch all after time interval method should be implemented"

Description

Implemented something different, than in #259 because the plan how we want to improve this changed. This should be also working with the planned upcoming changes to getting paths, adding mne, etc.

controller/event/event_test.go

@@ -158,7 +158,7 @@ func TestNewMneUpdateEvent(t *testing.T) {
 			}
 
 			if !reflect.DeepEqual(got.PathsAndValuesMap, tt.want.PathsAndValuesMap) {
-				t.Errorf("NewMneUpdateEvent().Type = %v, want %v", got, tt.want)
+				t.Errorf("NewMneUpdateEvent().PathsAndValuesMap = %v, want %v", got, tt.want)
 			}
 		})
 	}