Add tutorial section and Android part

Summary:
JS is next. Screenshot on the intro page is really bad.
I hope danielbuechele can replace this. :)

Reviewed By: jknoxville

Differential Revision: D15184371

fbshipit-source-id: 2faaf46450d192ae400675c13b8d71fa1b7dab14

android/tutorial/src/main/java/com/facebook/flipper/sample/tutorial/plugin/SeaMammalFlipperPlugin.kt

@@ -34,7 +34,7 @@ class SeaMammalFlipperPlugin : FlipperPlugin {
 
     override fun runInBackground(): Boolean = true
 
-    private     fun newRow(row: FlipperObject) {
+    private fun newRow(row: FlipperObject) {
         connection?.send("newRow", row)
     }
 }