Better Boilers

Major rebuild of the project after several years dormant. Highlights:

- Ported to a current, actively-supported Forge 1.12.2 build; removed all
  dependency on the abandoned Concrete library.
- Reworked the entire Networking and event layers.
- Reworked the multiblock scanning system to be event-triggered and
  tick-budgeted instead of a blind periodic poll, fixing stale/incorrect
  multiblock validity detection.
- Completely redesigned the Turbine: new Shaft, Blade, and tiered Coil
  (Iron/Gold, Copper with Immersive Engineering) blocks, replacing the old
  vertical chamber/cap/gasket design with a scalable shaft-and-rotor-stage
  system. Output now scales with blade count, coil tier, and actual steam
  flow.
- Rebuilt the GUI system on a shared, modular framework instead of one-off
  screens per machine.
- Normalized internal naming and package structure throughout.