Ducted Fan: Hover throttle, stack node, fix rotation. Up connection strenghts globally

Hoverthrottle from Firespitter added to ducted fans.

Removed rotation from radial ducted fan .cfg now its done in the .mu

Added stack node to radial ducted fans.

Upped connection strength, using the formula we use in B9. It can't solve everything, but it goes a long way towards making lighter/shorter parts not flex like wet noodles.