feat: forked dev server

[pi0]

Resolves #29

Resolves #73

This PR adds back new architecture of forked dev server using citty and unjs/httpxy. With this we will have feature parity with the current upstream nuxi CLI (and more!)

The main difference between new implementation and previous, is that the main listener lives in the main Node.js process and requests will get proxied to the actual dev server listening on a random HTTP port. This adds little overhead but adds lots of stability without need to restart HTTP(s) server, tunnel, possible devtools and IDE extensions using a fully standalone controller host.

Another small feature I've added with this PR is to enable Node.js --enable-source-maps by default.

Previous:

Now:

[Eckhardt-D]

@pi0 @danielroe The one regression this brings is that bunx --bun nuxt dev no longer works because bun does not implement IPC on child processes yet. Now there is a silent exit 0 being called in childProc.on("close") and weird behaviour where it prints out the bun help 😆 I know this is Bun's responsibility to fix. But shall I open a issue anyway so people at least know the limitation?