Add Paralyze mode support

During team relay races it's unsafe to retrieve crashed quads because the course is continuously hot. In order to safely fly a backup quad with the primary quad crashed in the field (but powered up) it's necessary to:

* Disable arming, so that the crashed quad doesn't unintentionally arm as well. This is specifically a problem when a transmitter can send signals to all powered up receivers (like FrSky and others).
* Change VTX to an unused channel with low power output
* Turn off telemetry

This change introduces a new mode called paralyze which disables arming and prevents mode changes (except beeper). It can only be invoked while the quad isn't armed. Once it's invoked, the FC has to be power cycled. In order to invoke it, the mode needs to be in a disengaged state at least once, so that forgetting to flip the switch back after crashing doesn't immediately invoke graveyard on the backup quad.

_Legal disclaimer: I am making my contributions/submissions to this project solely in my personal capacity and am not conveying any rights to any intellectual property of any third parties._

src/main/interface/msp_box.c

@@ -92,6 +92,7 @@ static const box_t boxes[CHECKBOX_ITEM_COUNT] = {
     { BOXUSER3, "USER3", 42 },
     { BOXUSER4, "USER4", 43 },
     { BOXPIDAUDIO, "PID AUDIO", 44 },
+    { BOXPARALYZE, "PARALYZE", 45 },
 };
 
 // mask of enabled IDs, calculated on startup based on enabled features. boxId_e is used as bit index
@@ -269,6 +270,8 @@ void initActiveBoxIds(void)
     BME(BOXVTXPITMODE);
 #endif
 
+    BME(BOXPARALYZE);
+
 #ifdef USE_PINIOBOX
     // Turn BOXUSERx only if pinioBox facility monitors them, as the facility is the only BOXUSERx observer.
     // Note that pinioBoxConfig can be set to monitor any box.