Use new RCS structures

https://ksp-kos.github.io/KOS/structures/vessels/rcs.html
We can now query the direction and strength of the RCS thrusters.

lib_rcs_burn has some hard-coded values for the stock parts, though these will be wrong for the varients possible in KSP v1.11.

It would also be nice to be able to use other RCS parts in future without needing to make code changes.