feature: support grouping notifications by date or repository

[setchy]

📝 Provide a description of the new feature

https://github.com/notifications supports displaying notifications in two ways

• date
• repository

Currently gitify always will group by repository.

This feature suggestion is to match the experience of the official GitHub web interface

➕ Additional Information

No response

[AltinGruda]

Hey, can I work on this?

[setchy]

Hey, can I work on this?

Absolutely! That would be greatly welcomed 🙏