Initial support for multiple OSD layouts

- Add 3 new boxes that can be controlled by a switch to toggle
between the default and 3 alternate layouts.
- Add new MSP cmds to retrieve/set the whole layouts, the OSD alarms
and the preferences.
- For now, CMS and settings just see the default layout. This
will be addressed on future commits.

src/main/fc/rc_modes.c

@@ -41,7 +41,15 @@ static bool isUsingNAVModes = false;
 #endif
 
 boxBitmask_t rcModeActivationMask; // one bit per mode defined in boxId_e
-STATIC_ASSERT(CHECKBOX_ITEM_COUNT <= 32, too_many_box_modes);
+
+// TODO(alberto): It looks like we can now safely remove this assert, since everything
+// but BB is able to handle more than 32 boxes and all the definitions use
+// CHECKBOX_ITEM_COUNT rather than hardcoded values. Note, however, that BB will only
+// log the first 32 flight modes, so the ones affecting actual flight should be <= 32.
+//
+// Leaving the assert commented for now, just in case there are some unexpected issues
+// and someone else has to debug it.
+// STATIC_ASSERT(CHECKBOX_ITEM_COUNT <= 32, too_many_box_modes);
 
 PG_REGISTER_ARRAY(modeActivationCondition_t, MAX_MODE_ACTIVATION_CONDITION_COUNT, modeActivationConditions, PG_MODE_ACTIVATION_PROFILE, 0);
 PG_REGISTER(modeActivationOperatorConfig_t, modeActivationOperatorConfig, PG_MODE_ACTIVATION_OPERATOR_CONFIG, 0);