Procedural Fairings: Move the thrust plate to be with the interstage parts

[bigyihsuan]

I found myself wishing I had an early-game engine mount, and realized that with the previous configs, you needed to get to after the Titan to get it. This pull request moves the thrust plate to be in the construction2 node with the other interstages.

[bigyihsuan]

(Disregard the number of commits, all of them except the last one is to get my local branch updated with the main one)