[SUGGESTION] Steerable main wheels

It would be nice to have steerable main wheels with and without free-
castoring. Steerable main wheels are a common use case in float planes, where
the front pair of wheels are free-castoring and in some cases (B-52 for one)
steerable. Sorry if I’ve posted this before.

This is used by few commercial aircraft as well. For instance B77W, B744,
B748.