Crosslink FlutterFire plugins (flutter-team-archive#129)

* Crosslink FlutterFire plugins

* Fix links

Author: mit-mit

packages/firebase_analytics/README.md

@@ -4,6 +4,8 @@
 
 A Flutter plugin to use the [Firebase Analytics API](https://firebase.google.com/docs/analytics/).
 
+For Flutter plugins for other Firebase products, see [FlutterFire.md](https://github.com/flutter/plugins/blob/master/FlutterFire.md).
+
 *Note*: This plugin is still under development, and some APIs might not be available yet. [Feedback](https://github.com/flutter/flutter/issues) and [Pull Requests](https://github.com/flutter/plugins/pulls) are most welcome!
 
 ## Usage

packages/firebase_auth/README.md

@@ -3,6 +3,8 @@ A Flutter plugin to use the [Firebase Authentication API](https://firebase.googl
 
 [![pub package](https://img.shields.io/pub/v/firebase_auth.svg)](https://pub.dartlang.org/packages/firebase_auth)
 
+For Flutter plugins for other Firebase products, see [FlutterFire.md](https://github.com/flutter/plugins/blob/master/FlutterFire.md).
+
 *Note*: This plugin is still under development, and some APIs might not be available yet. [Feedback](https://github.com/flutter/flutter/issues) and [Pull Requests](https://github.com/flutter/plugins/pulls) are most welcome!
 
 ## Usage

packages/firebase_database/README.md

@@ -4,6 +4,8 @@
 
 A Flutter plugin to use the [Firebase Realtime Database API](https://firebase.google.com/products/database/).
 
+For Flutter plugins for other Firebase products, see [FlutterFire.md](https://github.com/flutter/plugins/blob/master/FlutterFire.md).
+
 *Note*: This plugin is still under development, and some APIs might not be available yet. [Feedback](https://github.com/flutter/flutter/issues) and [Pull Requests](https://github.com/flutter/plugins/pulls) are most welcome!
 
 ## Usage

packages/firebase_messaging/README.md

@@ -6,6 +6,8 @@ A Flutter plugin to use the [Firebase Cloud Messaging (FCM) API](https://firebas
 
 With this plugin, your Flutter app can receive and process push notifications as well as data messages on Android and iOS. Read Firebase's [About FCM Messages](https://firebase.google.com/docs/cloud-messaging/concept-options) to learn more about the differences between notification messages and data messages.
 
+For Flutter plugins for other Firebase products, see [FlutterFire.md](https://github.com/flutter/plugins/blob/master/FlutterFire.md).
+
 *Note*: This plugin is still under development, and some APIs might not be available yet. [Feedback](https://github.com/flutter/flutter/issues) and [Pull Requests](https://github.com/flutter/plugins/pulls) are most welcome!
 
 ## Usage

packages/firebase_storage/README.md

@@ -4,6 +4,8 @@
 
 A Flutter plugin to use the [Firebase Cloud Storage API](https://firebase.google.com/products/storage/).
 
+For Flutter plugins for other Firebase products, see [FlutterFire.md](https://github.com/flutter/plugins/blob/master/FlutterFire.md).
+
 *Note*: This plugin is still under development, and some APIs might not be available yet. [Feedback](https://github.com/flutter/flutter/issues) and [Pull Requests](https://github.com/flutter/plugins/pulls) are most welcome!
 
 ## Usage