io-network: rework furnaces

[kukeiko]

What

Rework furnace code so that it fills up furnaces with any smeltable items provided by the player (as opposed to only filling up existing stacks in furnaces).

• the player provides fuel & smeltable items in a dedicated furnace input chest
• the io-network distributes those items into any connected furnaces
• the io-network distributes smelted items into a dedicated furnace output chest
• empty buckets are put into storage chests (so that lava turtles can suck them out from their bottom storage chest)

Notes

This will break existing furnace logic - which is fine as this new io-network version is used in a completely new base, and the code of the old base won't be updated.

Todo

• move items from furnace input chests into furnaces
• move items from furnaces to furnace output chests
• move empty buckets to storages
• prioritize fueled furnaces when distributing smeltables
• somehow prevent spamming all furnaces with 1x type of item; e.g. a cobblestone generator should not block player provided smeltables