796b020c37 wallet: add taproot support to external signer (Sjors Provoost)
Pull request description:
Builds on #22558 (merged on 2022-06-28).
[HWI 2.1.0](https://github.com/bitcoin-core/HWI/releases/tag/2.1.0) or newer is required to import and use taproot descriptors. Older versions will work, but won't import a taproot descriptor.
Tested with HWI 2.1.1:
* Trezor T (firmware v2.5.1) on Signet: signs, change detection works
* Ledger Nano S (firmware 2.1.0, Bitcoin app 2.0.6): signs, change detection works
Only the most basic `tr(key)` descriptor is supported, script path spending is completely untested (if it works at all).
ACKs for top commit:
jb55:
utACK 796b020c37
achow101:
ACK 796b020c37
Tree-SHA512: 6dcb7eeb45421a3bbf2bdabeacd29979867db69077d7bf192bb77faa4bfefe446487b8df07bc40f9457009a88e598bdc09f769e6106fed2833ace7ef205a157a
If there are multiple external signers, `GetExternalSigner()` will
just pick the first one in the list. If the user has two or more
hardware wallets connected at the same time, he might not notice this.
This PR adds a check and fails with suitable message.
The previous diff touched most files in ./test/, so bump the headers to
avoid having to touch them again for a bump later.
-BEGIN VERIFY SCRIPT-
./contrib/devtools/copyright_header.py update ./test/
-END VERIFY SCRIPT-
