feat: option to print hex

[thesimplekid]

I mostly use this crate for testing where I need the hex key or id not the bech32, this adds an argument to print the hex.

[0xtrr]

Thanks for this contribution @thesimplekid. Initially I wanted to always print both the hex and the bech32 id but I think this makes more sense. And if you need to encode/decode it, there's a command for that too.

[thesimplekid]

Thanks, I've been using that encode/decode just an extra step