Merge bitcoindevkit/bdk#1523: bdk_wallet: Don't reimplement descriptor checksum,...

70c7d6b1c064103b359ad2e774a2648fbd85a414 bdk_wallet: remove unnecessary calls to calc_checksum (Antoine Poinsot)
8245fb7eabb3aa9747118cc871dca4646be4d6e8 bdk_wallet: don't reimplement checksum algorithm, use rust-miniscript (Antoine Poinsot)
a11ace20ce38c9753d7f58cd410da747f4e4fd00 bdk_wallet: descriptor: remove unnecessary call to calc_checksum_bytes (Antoine Poinsot)

Pull request description:

  Skimming through the BDK code today i noticed the descriptor checksum algorithm is re-implemented instead of using the implementation from rust-miniscript. Re-implementing it here is more code to review and maintain, more room for mistakes and overall less eyes over the code than centralizing a single implementation over at `rust-miniscript`.

  While doing this i noticed that one of the variants was completely unnecessary (`calc_checksum_bytes`), so i removed it. I realise it's breaking the API, so if we want to avoid that i can remove this part. I also added a commit to remove redundant calls to `calc_checsum`.

  Overall this is just a quick PoC as i noticed it i figured i'd send a PR, my bad if i missed anything!

ACKs for top commit:
  storopoli:
    utACK 70c7d6b1c064103b359ad2e774a2648fbd85a414
  evanlinjin:
    ACK 70c7d6b1c064103b359ad2e774a2648fbd85a414

Tree-SHA512: 89d0e582979c8260a97646abc3821a9ec1fd84b5ff1e9236efa87654bd31d5da654c9725f4e1c9871a28c9312c0cfe6e095e50742abe5fbd0490fc9a2e41c86b