powerCheck: add power redundancy check

A parameter spcifies what the redundancy level for 5V rail supply
needs to be and a check makes sure that it's available before
taking off such that the user is aware of a broken or disconnected
redundant power module.

src/modules/commander/commander_params.c

@@ -912,3 +912,15 @@ PARAM_DEFINE_FLOAT(COM_KILL_DISARM, 5.0f);
  * @increment 1
  */
 PARAM_DEFINE_FLOAT(COM_CPU_MAX, 90.0f);
+
+/**
+ * Required number of redundant power modules
+ *
+ * This configures a check to verify the expected number of 5V rail power supplies are present. By default only one is expected.
+ * Note: CBRK_SUPPLY_CHK disables all power checks including this one.
+ *
+ * @group Commander
+ * @min 0
+ * @max 4
+ */
+PARAM_DEFINE_INT32(COM_POWER_COUNT, 1);