drip period &fertility tracker

Invalid date

New
- Make the app compatible with Android 13
- Chart: Improved readability
- Reminders: requesting notification permission right at the start (Android 13 requirement)
- Stats: Show period details, including cycle start, cycle length and amount of days with bleeding
- Stats: Explainer text for standard deviation
- Settings: Privacy Policy

Fix
- Password: Disable setting empty passwords
- Chart: Grid for symptoms and horizontal lines in temperature chart