Add just recipe for serving the js script

[andreiltd]

This recipe will compile starling.wasm, componentize and serve the component with wasmtime.

[guybedford]

The test service https://http-me.glitch.me/ is currently down - we might need to find a replacement, but we've alerted the team at Fastly that maintains that.

Can we add this to the README in the Just section. Alternatively it could be time to setup a DEVELOPMENT.md and make the README more end-user approachable.

[andreiltd]

The test service https://http-me.glitch.me/ is currently down - we might need to find a replacement, but we've alerted the team at Fastly that maintains that.

It looks like it's back again. Could you please poke the CI in other PR: #200. I don't have permission to rerun CI jobs.

Alternatively it could be time to setup a DEVELOPMENT.md and make the README more end-user approachable.

I think that's a good idea, I can prepare a separate PR for this. What would you imagine go into the DEVELOPMENT.md? Everything starting from WPT tests, and leave the first paragraph as a quickstart section?

[guybedford]

It might be worth simplifying the first section to a copy-paste case, and then having the full info in the DEVELOPMENT.md as well.