This is a partial backport of core#20220
Most of the PR is not applicable because we do not use estimate_mode nor conf_target for fees.
List of changes and source commits:
- Use a const ref in FundTransaction for options: https://github.com/bitcoin/bitcoin/pull/20220/commits/1697a40b6f841a54ee0d9744ed7fd09034b0ddad
- Minor rpc_psbt.py refactoring: https://github.com/bitcoin/bitcoin/pull/20220/commits/6e1ea4273e52fdcd86c87628aa595c03a071ca8c
- Add a log.info in wallet_basic.py: https://github.com/bitcoin/bitcoin/pull/20220/commits/dd341e602d5160fc621c0299179b91403756b61d
- Improve RPC doc for subtract_fee_from_outputs: https://github.com/bitcoin/bitcoin/pull/20220/commits/778b9be40667876c705e586849ea9c9e44cf451c