[backport#15427 3/3] Add support for descriptors to utxoupdatepsbt

Summary:
This adds a descriptors argument to the utxoupdatepsbt RPC. This means:

• Input and output scripts and keys will be filled in when known
• P2SH-witness outputs will be filled in from the UTXO set when a descriptor is provided to show they're segwit outputs.

https://github.com/bitcoin/bitcoin/pull/15427/commits/26fe9b990995f9cb5eee21d40b4daaad19f7181f

Depends on D6624

Concludes backport of Core PR15427

Test Plan:

ninja check-all

Reviewers: #bitcoin_abc, Fabien, deadalnix

Reviewed By: #bitcoin_abc, Fabien, deadalnix

Subscribers: deadalnix, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D6626