signmessage: also accept Trezor-type sigs for p2wpkh and p2wpkh-p2sh addrs

[SomberNight]

see #3861:

there is no clear consensus how to sign messages with segwit addresses (txin type of p2wpkh-p2sh and p2wpkh)
We do one thing, and Trezor does something else. Bitcoin Core has this disabled.

This PR only changes the signature verification we do:

• the signatures we create are unchanged,
• but we now also accept signatures created by Trezor and others.

closes #3861
closes #7660

[bitromortac]

For my understanding: the difference between the signature approaches is that Electrum treats all segwit signatures as if it would be for a compressed legacy address but Trezor encodes the address type in the signature header. So this address type can then be used to check the given address with the address derived from the signature pubkey, but Electrum just brute forces the address check. So far looks good to me.

[massmux]

I tested this patched branch and works as a charm. Anxious to see it merged into the main branch