Implement TopUp in DescriptorScriptPubKeyMan

Summary:
Backport of Core PR16528 [21/43] : https://github.com/bitcoin/bitcoin/pull/16528/commits/58c7651821b0eeff0a99dc61d78d2e9e07986580

Depends on D8417

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Subscribers: majcosta

Differential Revision: https://reviews.bitcoinabc.org/D8419