Documentation for workerd

[KianNH]

This discussion is purely just to see what direction the Workers team was taking with documentation for workerd specifically. A few ideas off the top of my head:

• A more in-depth guide for configs to build on-top of the example in the README.
• Using workerd compile or creating the configs using a Cap'n Proto serialisation library in a given language.
• Actually running workerd, expanding on the systemd example.
• Building workerd, where to get pre-built binaries from (npm), etc.

Mainly, if that sort of content is wanted and if it'd go in the Cloudflare developer documentation or just in the /docs/ folder in this repository.

Lots of the information already exists in various documentation around the repo but expanding on those with more advanced examples/use-cases would be awesome.

[kentonv]

Agreed we need to do better here.

I don't have strong opinions on how to do it, though.

Maybe @jasnell and/or @mrbbot have thoughts.