Don't send NodeInfo and DeviceTelemetry at high Tx air util

Also move airtime checking to airtime class

src/mesh/SinglePortModule.h

@@ -18,9 +18,6 @@ class SinglePortModule : public MeshModule
     SinglePortModule(const char *_name, PortNum _ourPortNum) : MeshModule(_name), ourPortNum(_ourPortNum) {}
 
   protected:
-    uint32_t max_channel_util_percent = 40;
-    uint32_t polite_channel_util_percent = 25;
-
     /**
      * @return true if you want to receive the specified portnum
      */