feat(node-server): implement socket activation

[septatrix]

🔗 Linked issue

This expands upon #1129.

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This implements the LISTEN_FDs socket activation protocol to allow starting the server by passing a preconfigured socket file descriptor. This is useful to allow an unprivileged process to bind to privileged ports or addresses outside the namespace.

Testing can be done using the following commands:

# Bind to single port
systemd-socket-activate -l 8000 node playground/.output/server/index.mjs
# Bind to unix socket (this triggers the `addressInfo === null` codepath)
systemd-socket-activate -l ./socketname node playground/.output/server/index.mjs
# Bind to multiple ports, only first passed FD will be used (see code)
systemd-socket-activate -l 8000 -l 9000 node playground/.output/server/index.mjs

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[pi0]

Thanks for PR ❤️ Since Nitro v3 will be based on srvx can you please raise an issue there to first discuss the API design? 🙏🏼 (we need to consider supporting Node, Deno and Bun and perhaps using an approach to use a srvx plugin to be opt-in)

(closing PR mainly for triage)