stacks-signer generate-stacking-signature CLI parses BTC address incorrectly

[hstove]

The generate-stacking-signature command in stacks-signer uses PoxAddress::from_b58(), which is actually designed to convert a BTC address into a STX address. What I mean is that it converts a mainnet p2pkh address (aka version 0) into a PoX address with the Stacks mainnet p2pkh version (aka 22).

The problem is that I'm converting this to a Clarity tuple, for use with Stacking, which results in incorrect values.

I'm working on a fix that adds a new function to convert a BTC address string into a PoX address that can be used with pox-4, similar to this function in stacks.js