Wallet Privacy Improvements

This is a tracking issue for wallet privacy features mentioned but not completed in bitcoindevkit/bdk#918. Some of these will require bitcoindevkit/bdk_wallet#188.

> I'm doing some bitcoin core repo archeology to identify privacy related wallet features. I started with the excellent [core onboarding wallet write up](https://github.com/chaincodelabs/onboarding-to-bitcoin-core/blob/master/04_wallet.adoc) from @willcl-ark, which mentioned choosing an "appropriate" change script type. I have identified the below features BDK's wallet API should support. Some of these we already support, the rest I'll make new BDK issues for. Please comment if you know of any I'm missing.

- [x] bitcoin/bitcoin#2340, fixed in bitcoindevkit/bdk#611
- [ ] bitcoin/bitcoin#12119
- [ ] bitcoin/bitcoin#12257, WIP bitcoindevkit/bdk#1851
- [ ] bitcoin/bitcoin#13756
- [ ] bitcoin/bitcoin#13808
- [ ] bitcoin/bitcoin#16512
- [ ] bitcoin/bitcoin#16528, the part about 6 descriptors is useful
- [ ] bitcoin/bitcoin#17621
- [ ] bitcoin/bitcoin#18418, WIP bitcoindevkit/bdk#1851
- [ ] bitcoin/bitcoin#23789
- [ ] bitcoin/bitcoin#24494
- [ ] bitcoin/bitcoin#24584

_Originally posted by @notmandatory in [#918](https://github.com/bitcoindevkit/bdk/issues/918#issuecomment-1491221046)_