Merge bitcoindevkit/bdk#1040: Add cli esplora example

f41cc1cb374d6bae553dd997ebb325ced21025f0 fix: s/index_tx_graph/indexed_tx_graph/g (LLFourn)
da8cfd39e9733f6da12b0fe10b8ccf5e5894e090 feat: add cli example for `esplora` (志宇)

Pull request description:

  ### Description

  This PR builds on top of #1034 and adds a cli-example for our `esplora` chain-src crate.

  ### Notes to the reviewers

  Don't merge this until #1034 is merged. The only relevant commit is 5ff0412d8edba933760c79a40be29c8365719096.

  ### Changelog notice

  * Add cli-example for `esplora`.

  ### 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~
  * [x] I've added docs for the new feature

ACKs for top commit:
  danielabrozzoni:
    ACK f41cc1cb374d6bae553dd997ebb325ced21025f0
  notmandatory:
    ACK f41cc1cb374d6bae553dd997ebb325ced21025f0

Tree-SHA512: a41fa456a9509f75feea0af013deaaad846cc6b60e5e6671672630a716e8c962361cbc9bb2d62c68e96d5fdb9e580912c19ff5fcab1acaf604b5b4a10eb40cee