Merge bitcoindevkit/bdk#1840: example_cli: add feerate option to psbt new cmd

c855a0942bafe1211308d887e8bc0de82c95cc68 refactor(example_cli): clean up CLI docs (valued mammal)
b9be1f43eeb4c822242962082de86ebd64f7410c deps(example_cli): bump `bdk_coin_select` to 0.4 (valued mammal)
3e640ff93d375a06678052befa45e6356949bff4 feat(example_cli): add feerate option to psbt new cmd (valued mammal)
1ab269e54881189b5f149d1941f804d780fd29d7 example_cli: fix collect assets with `for_each_key` (valued mammal)

Pull request description:

  The PR aims to add a `--feerate` option to the psbt `New` command.

  Also in this PR:

  - bump `bdk_coin_select` to 0.4
  - fix collecting `Assets` and enable support for more descriptor types

  ### Changelog notice

  ### 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

ACKs for top commit:
  ValuedMammal:
    ACK c855a0942bafe1211308d887e8bc0de82c95cc68

Tree-SHA512: f6a4d8d793c5258690bae397bcb3992e2c83ea21f0808e2d58c471d15aa160882873c336e71354e6c948aa9850cd62cfb53379365db79f98a9b1937a6abc2c7e