Add a way to hide item usage by a rocket silo from stats

[Muppet9010]

At present the items sent in a rockets inventory and the items that are created in the rocket silos result inventory can't be hidden from production stats like a recipe in an assembling machine can be.

As suggestions I think this could be resolved by either:

1. New attributes on an item prototype to hide from rocket silo production stats and to hide from rocket inventory consumption stats.
2. New attribute on the rocket silo to hide a list of items from production stats when they are created as the result. New attribute on the rocket to hide a list of items from consumption stats when the rocket is "done" flying.