HITL handling: Enforce the use of the activation parameter for HITL configuration

src/modules/systemlib/system_params.c

@@ -64,6 +64,18 @@ PARAM_DEFINE_INT32(SYS_AUTOSTART, 0);
  */
 PARAM_DEFINE_INT32(SYS_AUTOCONFIG, 0);
 
+/**
+ * Enable HITL mode on next boot
+ *
+ * Set to 1 to enable HITL on next boot. The system will automatically
+ * reset it on reboot.
+ *
+ * @value 0 HITL off
+ * @value 1 HITL on
+ * @group System
+ */
+PARAM_DEFINE_INT32(SYS_HITL, 0);
+
 /**
  * Set usage of IO board
  *