Fix defect in CB design of backup switch

Referring to the posts

https://webuildplanes.com/adam-dickson-sling2/p/7328/revised-panel-cb-arrangement-and-busbar-structure

There remains a defect in this design, namely the main bus feeds directly into the MS35058 backup/main switch. This switch is rated to 15-20A and will be overloaded by the main bus which is protected by a 30A CB, in the event of a short downstream of this switch (but upstream of any CBs). The solution is to insert a 15A CB in this path, however this would necessitate squeezing an additonal CB onto the panel. The solution is the move the REG CB below the master switch, and the START CB alongside the ignition switch. An ESS BUS breaker would go in the place of the REG CB