Send dir listing as a stream or single request

[5HT2]

I don't think an fmt.Fprintf for each individual file is the best idea for large directories, given my screenshots folder is reaching ~5000 screenshots.

Below is the current code for printing it:

https://github.com/l1ving/fs-over-http/blob/bdd0e31a7cea69d470fe23a07aa04b991acd303c/main.go#L255-L282

Sending it as one request or a stream would be ideal.