touch ./animations (#148)

* Update project structure using flutter create and remove unused tests
* Small updates to main.dart
* Update maintenance.md
* Add missing newline
* Add rudimentary test
* Apply formatting

animations/android/app/src/main/kotlin/com/example/animations/MainActivity.kt

@@ -0,0 +1,13 @@
+package com.example.animations
+
+import android.os.Bundle
+
+import io.flutter.app.FlutterActivity
+import io.flutter.plugins.GeneratedPluginRegistrant
+
+class MainActivity: FlutterActivity() {
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    GeneratedPluginRegistrant.registerWith(this)
+  }
+}