Prepare for federated packages

example/android/.gitignore

@@ -1,13 +0,0 @@
-gradle-wrapper.jar
-/.gradle
-/captures/
-/gradlew
-/gradlew.bat
-/local.properties
-GeneratedPluginRegistrant.java
-
-# Remember to never publicly share your keystore.
-# See https://flutter.dev/docs/deployment/android#reference-the-keystore-from-the-app
-key.properties
-**/*.keystore
-**/*.jks