[skip ci] Remove useless files and solve AGP warnings (#1575)

* chore: Remove useless files

* [skip ci] refactor: Solve deprecation warnings from AGP

multisrc/src/main/java/generator/ThemeSourceGenerator.kt

@@ -108,7 +108,7 @@ interface ThemeSourceGenerator {
                     """
                     |<?xml version="1.0" encoding="utf-8"?>
                     |<!-- THIS FILE IS AUTO-GENERATED; DO NOT EDIT -->
-                    |<manifest package="eu.kanade.tachiyomi.animeextension" />
+                    |<manifest />
                     """.trimMargin(),
                 )
             }