Port to Rust

Hi @anthonykirby,

We at @tago-io have ported the `lora-packet` library to Rust since we are heavy users of it.

This issue is just to let you know. Our port is based on this repository, and we've properly referenced it in our license.

Thank you! You're welcome to contribute to the Rust port if you'd like.

https://github.com/tago-io/lora-packet-rs