Command to verify torrent file data

We need a command or tool that can verify torrent data in place without going through `--downloader.verify`

Additionally it will serve the needs of `downloader --verify.failfast --verify.files=a,b,c`

I'll add a subcommand to the anacrolix/torrent/cmd/ tooling, and then also expose that same functionality as an erigon subcommand so no extra tooling is required