This PR contains a suggested implementation for reworking the dark mode of the MediaInfo Android app.

Changes:

• The dark mode now defaults to follow the OS setting while overriding it to force light or dark mode regardless of OS setting remains a premium feature.
• The dark mode for report views now uses native dark mode/theme of WebView.

Reason:

• Dark mode has become an essential feature in modern apps and OS
  • Android 16 QPR2 has a feature to force dark mode on all apps
    • This means MediaInfo app will be forced to follow OS dark mode if this setting is enabled even without subscription
    • However this results in non-optimal display compared to a proper dark mode
  • There have been complaints in reviews about dark mode being a paid feature in MediaInfo
  • Even Microsoft is now implementing dark mode for the remaining Windows 11 dialogs that not yet have dark versions
• Android WebView has built-in dark mode and the HTML generated by MediaInfoLib now supports dark mode as well.
  • There is no need to manually override the colours of the report WebView anymore. Instead, using the built-in dark mode results in more consistent colours with the rest of the system.

Other changes in this PR not related to dark mode:

• Migrate ReportDetailFragment menu to MenuProvider API
  • The previously used API has been deprecated for use in fragments. It is not yet deprecated for activities so the one in main activity is not yet migrated.
• Migrate to Activity Result API for ReportDetailFragment and ReportListActivity
  • The previously used API is deprecated
  • Using new API results in less code needed too
• Migrate to ViewPager2
  • androidx.fragment.app.FragmentStatePagerAdapter is deprecated
  • https://developer.android.com/develop/ui/views/animations/vp2-migration
• Fix English grammar in subscription condition text.
• Remove API checks that are no longer needed
  • MediaInfo app no longer supports older Android versions so these checks for older APIs are no longer necessary.
• Resolve most warnings to reduce the amount of warnings in Android Studio.

These non-dark-mode-related changes (other than the English correction) should not have any visible changes to users of the app.