Merge bitcoindevkit/bdk#1412: Add new crate `bdk-persist`

81de8f60516899fad2ec99cbd15d6b8d02385ebb feat(bdk-persist): extract persistence traits to new crate (Rob N)

Pull request description:

  ### Description

  #1387 introduced `anyhow` as a dependency to remove generics from `Wallet`. Introducing a new crate for persistence types removes the dependency on `anyhow` for `bdk_chain`. Resolves #1409, as well as removing the old documentation for "tracker".

  ### Notes to the reviewers

  Open for any comments.

  ### Changelog notice

  - Introduce `bdk-persist` crate

  ### Checklists

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [x] I ran `cargo fmt` and `cargo clippy` before committing

  #### New Features:

  * [ ] I've added tests for the new feature
  * [ ] I've added docs for the new feature

  #### Bugfixes:

  * [ ] This pull request breaks the existing API
  * [ ] I've added tests to reproduce the issue which are now passing
  * [x] I'm linking the issue being fixed by this PR

ACKs for top commit:
  evanlinjin:
    ACK 81de8f60516899fad2ec99cbd15d6b8d02385ebb

Tree-SHA512: 29b192b13f3951cc67c06bec7f788d8d7a4aeaf2ffcbf9476d4a6567529d284a93594c8d94b69741a68a9aadfdc9f6c4178084a2298c505e8e0d505219400382