Add node: prefix to all built-in Node.js imports

[sntran]

Describe the bug
The library uses a couple Node.js built-in modules like fs, events, net, tls, stream and path. It would be great if their imports have node: prefix. The goal is to make it comparable with other runtimes like Cloudflare Workers (pending cloudflare/workerd#2217) and Deno. The changes required are minimal, but can widen the audience of the library.

[patrickjuchli]

This library supports Node 10. When exactly was the prefix node: introduced? Is it backwards-compatible?

Depending on a later version of Node will require this library to release a new major version.

[sntran]

Ah. The node: prefix was introduced in v14.13.1, v12.20.0 so it won't be backward compatible for Node 10.x.

What's about releasing a separate ESM version with the prefix? Older Node.js can use the CJM require as normal.