Merge #13658: [moveonly] Extract RescanWallet to handle a simple rescan

Summary:
3fe836b78d504942e8850b607453886969f57e27 [moveonly] Extract RescanWallet to handle a simple rescan (Ben Woosley)

Pull request description:

Where the outcome does not depend on the result, apart from a simple
success check.

Tree-SHA512: e0d29c6fc0c7f99a730289e5a80deb586b2848aead56b5198a71ef01f65374812468dfd57be0b8b076eb9be4090d5101d28d979a1d5c3d2f1caeca77b303e90e

Backport of Core PR12658
https://github.com/bitcoin/bitcoin/pull/13658/

Test Plan:

make check
./bitcoin-qt -> help -> debug -> console -> rescanblockchain
./bitcoind
./bitcoin-cli rescanblockchain

Reviewers: deadalnix, Fabien, jasonbcox, O1 Bitcoin ABC, #bitcoin_abc

Reviewed By: jasonbcox, O1 Bitcoin ABC, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D4020