Require "node:stream" instead of "stream"

[boenrobot]

And adjust minimum nodejs version accordingly.

Also removed package-lock.json and added it to .gitignore.

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Using "node:stream" instead of "stream" enable use of this library in runtimes other than nodejs (e.g. workerd), at the cost of leaving behind older Nodejs versions.

The package-lock.json is unnecessary in a library, especially when not in a monorepo under CI. It generated a lockfile with older versions due to me testing at 14.18.0 and its bundled npm, while I imagine the latest used was newer.