Add item filter for train networks

Add a whitelist (or blacklist, or maybe both) to filter out what can be transported via a certain train network.
With the new station arrival conditions, we can estimate to have more complicated station design that handles various type of goods at the same time.
Adding filters will give us the exact control of the network behavior so that it can work better along with "traditional" train lines.

Or you could just handle this yourself by not networking supply stations that provide goods you don't want.
I've already done this in my save. My Rock output from my various terraforming projects proved to be just too much for my network to handle, so I removed the rock supply stations from the network and set up a dedicated rock line.