BIP 326 Anti Fee Sniping

[benthecarman]

Describe the enhancement

BDK currently has anti-fee sniping implemented, however it just sets the transaction locktime to the current height.

This can be improved by implementing BIP-326 which is designed to be more privacy preserving for the rest of the network, specifically for taproot transcations.

https://github.com/bitcoin/bips/blob/master/bip-0326.mediawiki

[notmandatory]

Since this is a functional change I moved it to the alpha.4 release. If we don't think we'll be able to implement it right now I'll move it to the 1.1 feature release.

[ValuedMammal]

@benthecarman How does this bip326 implementation look to you so far? bitcoindevkit/bdk@master...ValuedMammal:bdk:feat/bip326-afs

[benthecarman]

Looking pretty good so far, you should make it a PR so people can comment on it

[notmandatory]

I propose we push to to a post 1.0 release since it's a functional improvement that shouldn't change the current wallet API.