`badfiles` should offer to try fix broken files

I've used this [guide](https://www.blisshq.com/music-library-management-blog/2020/12/09/repair-flac-files/) to fix flac files that badfiles has alerted me to.

```
flac -VFf --preserve-modtime -o fixed.flac corrupted.flac
```

`mp3val` also seems to have the following [options](https://mp3val.sourceforge.net/docs/manual.html):

```
mp3val -f -si -nb -t corrupted.mp3
```

I'd be happy to work on implementing this.

### Proposed solution

`badfiles` should provide the option to automatically try and resolve errors in FLAC and mp3 files.

### Objective

It would be useful if `badfiles` would offer to try and fix errors for FLAC and mp3 files.

#### Goals

Fixable FLAC and mp3 files should (optionally) be automatically fixed.

#### Non-goals

This could potentially be extended to resolve errors for other formats, but is out of scope for this feature request.

#### Anti-goals

This should be optional and not default behaviour.