- Better contextual logging for YAML files
- When there's a syntax error in file parsing, skip that file.
- When validation fails for instance config, skip just that instance.
- If a file is empty, print a warning and skip it.
- Print instance name (instead of URL) in more places.
If custom formats are provided, run validation logic against them. This
also was an opportunity to make the ServiceConfiguration validation
logic reusable between Sonarr and Radarr.