Instead of having a hard limit of 3 (regular) tries for feeds with errors, use
an exponential backoff by default, with an upper-limit of one week.
See https://github.com/miniflux/v2/issues/3334 for context/discussions.
This PR refactors the configuration parser, replacing the old parser implementation with a new, more structured approach that includes validation and improved organization.
Key changes:
- Complete rewrite of the configuration parser using a map-based structure with built-in validation
- Addition of comprehensive validator functions for configuration values
- Renamed numerous configuration getter methods for better consistency