refs https://linear.app/tryghost/issue/CORE-35/refactor-route-and-redirect-settings
- Ensure settings had only one method but would benefit from class+DI pattern before extracting it into an outside module.
- The logic is now also less coupled with "routes" and single source/destination paths. It's all configureable instead and might be reused if similar pattern is needed for example with redirect settings defaults.
