Machines give a building input/output slots and their own timed recipes.
The server processes them, replicates their state and saves it with the
world. The furnace becomes a machine and an assembler is added as an
example with a custom window layout. The client window follows with the
new UI.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
