Add descriptors to listunspent and getaddressinfo + tests

Summary: This is a partial backport of Core PR14477 : https://github.com/bitcoin/bitcoin/pull/14477/commits/16203d5df755fe8fc0c5ddc026714d87b504ff24

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Differential Revision: https://reviews.bitcoinabc.org/D6136