Add `simfmt` into simplex as bundled binary

[ikripaka]

Describe the feature

Most functionality would be encapsulated in one binary inside https://github.com/BlockstreamResearch/simfmt/ as smplx-fmt, but simplex will bridge this parameters to simfmt and smplx-fmt.

Binaries located inside https://github.com/BlockstreamResearch/simfmt/:

• simfmt
• simplex-fmt

Entry to add to simplex:

• simplex fmt

Flags to add in a formatter option:

% simplex fmt -h
This utility formats all bin and lib files of the current crate using simfmt.

Usage: simplex fmt [OPTIONS] [-- <simfmt_options>...]

Arguments:
  [simfmt_options]...  Options passed to simfmt

Options:
  -q, --quiet
          No output printed to stdout
  -v, --verbose
          Use verbose output
      --version
          Print simfmt version and exit
      --manifest-path <manifest-path>
          Specify path to Simplex.toml
      --message-format <message-format>
          Specify message-format: short|json|human
      --all
          Format all packages, and also their local path-based dependencies
      --check
          Run rustfmt in check mode
  -h, --help
          Print help

What about packages?
-> By now, we don't have exact packages like in Rust, so this functionality is obsolete

  -p, --package <package>...
          Specify package to format

Files which will be edited:

• simplexup/simplexup - to download and check binary attestations from the simfmt releases
• smplx-cli - add an entry to bridge parameters inside the simplex-fmt binary
• .github/workflows/release.yml - add the ability to bundle simfmt and simplex-fmt binaries under the simplex release