Be able to create new wallets with DescriptorScriptPubKeyMans as backing

Summary: Backport of Core PR16528 [33/43] : https://github.com/bitcoin/bitcoin/pull/16528/commits/82ae02b1656819f4bd5023b8955447e1d4ea8692

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D8455