* Implement feature to selectively clear manga from database based on it's source
* Code cleanup and refactoring
(cherry picked from commit 9fe1a7e2ae14c4d7e70bfd85516d91c44514f04a)
# Conflicts:
# app/src/main/java/eu/kanade/tachiyomi/data/database/queries/MangaQueries.kt
# app/src/main/java/eu/kanade/tachiyomi/data/database/queries/RawQueries.kt
# app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsAdvancedController.kt
