Add Node JS example

[heri16]

Add example and binding for nodejs.

Behave the same as the built-in net.connect() or net.createConnection() API in nodejs.

Tested to work on node v12.18.0

See Issue #10

[joseph-henry]

@heri16 Thank you for this. I'm only just now getting to it but before I start testing it is there anything I should wait for or be aware of?

[joseph-henry]

@heri16 I've reviewed your PR and it appears to be quality work so I will merge it.

One minor licensing point however is that while example code/wrappers can be contributed as non-BSL (e.g. your use of MIT License), I will change the license field of package.json to BSL since it is referring to libzt which is Licensed under BSL.

If you would like to attach headers to your files stating that the contents themselves are licensed under MIT, that would be totally acceptable since you wrote it after all.

Thanks again for your contribution and let me know if you have any questions.