zombierecovery: support MuSig2 to rescue Simple Taproot channels

[guggero]

Fixes #133.

[hsjoberg]

Thank you for taking your valuable time to fix P2TR support for zombierecovery, @guggero.

When running this PR and trying to do makeoffer, it seemingly get stuck with no feedback.

Input your cipher seed passphrase (press enter if your seed doesn't have a passphrase): [enter]

Anything I could do to get us more info about what's going on?

Cheers

[guggero]

Hey, thanks for testing. I assume you hit "enter" a second time, just to make sure it's not just a weird console/terminal behavior? If yes, is the process actively doing anything, do you see CPU usage?
The only thing that could take a while is matching the keys. But unless you have thousands and thousands of keys in both files, it shouldn't take more than a couple of minutes.

[guggero]

I assume this works, as I haven't gotten any feedback yet stating otherwise. Going to merge, can always address issues later on.