fishnet: distributed Stockfish analysis for lichess.org

Experimental rewrite

This is an experimental rewrite of fishnet. Look there for the current version.

Goals

• Update to Stockfish 12 NNUE
• Reproducible analysis
• Modernize by rewriting in Rust or dropping old Python versions

Roadmap

• [ ] Application structure
• [ ] Signal handler
• [ ] Logging
• [ ] cpuid
• [ ] Stockfish selection and verification
• [ ] systemd helper
• [ ] Configuration
• [ ] Warn about Python versions on old fishnet
• [ ] Backwards compatibility
• [ ] Test run
• [ ] Publish to main repository