change time display to relative for rx messages

src/graphics/Screen.h

@@ -206,6 +206,9 @@ class Screen : public concurrency::OSThread
         }
     }
 
+    /// generates a very brief time delta display
+    String drawTimeDelta(uint32_t days, uint32_t hours, uint32_t minutes, uint32_t seconds);
+
     /// Overrides the default utf8 character conversion, to replace empty space with question marks
     static char customFontTableLookup(const uint8_t ch)
     {