Makes setting yt-dlp's `format` field easier by giving it its own documented plugin.
Old:
```
my_format_preset:
ytdl_options:
format: "best"
```
New:
```
my_format_preset:
format: "best"
```
The old method will still work, so do not worry about updating configs ASAP. However, the option is available to save a few lines 😉
* [BUGFIX] Do not fail with thumbnail issues
* helper
* refactor
* dry-run
* regen fixture
* download arhcive txt -> json in docs, fixtures
* return if no download thumb path
* better test
* more test coverage
* actually working
* changed plugin format. Need unit tests, documentation, update e2e to filter
* refactor plugin name, matching now working
* description work in progress, need more intricate testing
* tests looks good, regenerate output
* e2e tested, need more failure tests, no dupe variable names, add docs
* unit tests passing again
* more fail tests
* updated with name, default, better docs
* sanitized vars created
