Remove application tag in AndroidManifest.xml

mirai-core/src/main/AndroidManifest.xml

@@ -1,10 +1,3 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-          package="net.mamoe.mirai">
-
-    <application
-            android:allowBackup="true"
-            android:supportsRtl="true">
-    </application>
-
+<manifest package="net.mamoe.mirai">
 </manifest>