Merge bitcoindevkit/bdk#2006: refactor: replace examples with focused rustdoc examples

522e441a1a4511860a90c43c3932cd45a8797c15 chore: Remove example_cli (Kyle 🐆)

Pull request description:

  Closes #1973

  The PR is now scoped to the first step of the work discussed in #1973:

  - Remove the unmaintained example binaries in examples/
  - Remove the related workspace members from Cargo.toml
  - Clean up docs and CI references that pointed to the removed examples

ACKs for top commit:
  ValuedMammal:
    ACK 522e441a1a4511860a90c43c3932cd45a8797c15

Tree-SHA512: 217bbe23c0798903046eaf3f8638099d721c59bc26902fa5d9c3a0e3c3bcc6738b9a7e9b6e6ca82e3c1758aaffd69bec3e91cf00e5a6bf7e1da7c53cf23f1288