* Tweak flag classes for Library
- Add interface for Flag and Mask
- Merge Sort Type and Direction into one class
- Use custom serializers for preferences
- Mainly to not break the old
* Review changes
(cherry picked from commit 880407442c598d1b63db8be43f4848550dc17ff1)
# Conflicts:
# app/build.gradle.kts
# app/src/main/java/eu/kanade/domain/category/interactor/SetDisplayModeForCategory.kt
# app/src/main/java/eu/kanade/domain/category/interactor/SetSortModeForCategory.kt
# app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt
# app/src/main/java/eu/kanade/tachiyomi/ui/browse/source/browse/BrowseSourceController.kt
# app/src/main/java/eu/kanade/tachiyomi/ui/browse/source/browse/SourceItem.kt
# app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt
# app/src/main/java/eu/kanade/tachiyomi/ui/library/LibrarySettingsSheet.kt
# app/src/main/java/eu/kanade/tachiyomi/ui/library/setting/SortDirectionSetting.kt
# app/src/main/java/eu/kanade/tachiyomi/ui/library/setting/SortModeSetting.kt
