Merge bitcoindevkit/bdk-cli#48: adding the commands for proof-of-reserves using the...

7e6a4c848b0c7323ea12af074f38a42347a49fcc adding the commands for proof-of-reserves using the separate repository (Richard Ulrich)

Pull request description:

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  ### adding the commands for proof-of-reserves using the separate repository

  <!-- Describe the purpose of this PR, what's being adding and/or fixed -->

  ### Notes to the reviewers

  <!-- In this section you can include notes directed to the reviewers, like explaining why some parts
  of the PR were done in a specific way -->

  ### Checklists

  #### All Submissions:

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

  #### New Features:

  * [x] I've added tests for the new feature
  * [ ] I've added docs for the new feature
  * [x] I've updated `CHANGELOG.md`

  #### Bugfixes:

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

ACKs for top commit:
  notmandatory:
    ACK  7e6a4c8
  rajarshimaitra:
    ReACK https://github.com/bitcoindevkit/bdk-cli/pull/48/commits/7e6a4c848b0c7323ea12af074f38a42347a49fcc

Tree-SHA512: 3b2a02280ce0e6d9c6f061ac01d15ef3b2704c13bd6e55bfeacff4673d750d2bf93c242b87d88874d49a189207ce0990ce2882fe0a0111dfcb77f065e3d1efb9