Support Bitcoin Core descriptor wallets

[chris-belcher]

Basically the same issue as JoinMarket-Org/joinmarket-clientserver#1064

Bitcoin Core 23.0 will produce descriptor wallets by default, while EPS assumes legacy wallets. Old installations of EPS should still work but new installations might be a little bit harder to set up because legacy wallets will have to be specially created.

Note that EPS already uses descriptors (except for OldMnemonicWallet which probably very few people use), so it shouldnt be too hard. I haven't looked yet but it might be as using importdescriptor instead of importmulti.