Replace global flags with stateFlags, flightModeFlags and armingFlags.

Each flag was previously a whole byte, now all of the flags only take up
4 bytes as they are represented by bit masks.

This is cleaner because the different kind of flags are now separated.

Additionally this changes the behaviour of arming slightly.  When using
a switch to arm the aircraft will not arm unless the switch has been in
the off state once.  This prevents arming if you power the aircraft with
a low throttle and the switch in the on position.

src/main/telemetry/telemetry.c

@@ -105,7 +105,7 @@ bool determineNewTelemetryEnabledState(void)
         if (telemetryConfig->telemetry_switch)
             enabled = rcOptions[BOXTELEMETRY];
         else
-            enabled = f.ARMED;
+            enabled = ARMING_FLAG(ARMED);
     }
 
     return enabled;