Added ClonesProductionUnits trait for RA2-style Cloning Vats

Yep we're in a feature freeze.
Yep we don't have RA2 yet.

I think mod authors will be happy to have this a few games early.
Can we have a nice, long description here?

It took me a while to understand what it does and I'm still not sure I got it right: it monitors what all other factories of the same owner produce and it adds it to its own production queue if it's in the `CloneableTypes` list. Right?