feat: add configurable mail model, events model, and resource settings (#8)

* feat: add configurable mail model, events model, and resource settings

- Add configurable mail and event models via config
- Add configurable resource settings (navigation group, label, slug, icon)
- Fix table name configuration in models via constructor
- Fix migration to use configurable table names and models
- Update all references to use config instead of hardcoded models

* Fix styling

* feat: base docs

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Co-authored-by: danielhe4rt <6912596+danielhe4rt@users.noreply.github.com>

Author: danielhe4rt