Create android & web plugins (#15)

* create android & web plugins

* apply `flutter format .`

android/src/main/AndroidManifest.xml

@@ -0,0 +1,3 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+  package="io.livekit.plugin">
+</manifest>

android/src/main/kotlin/io/livekit/plugin/LiveKitPlugin.kt

@@ -0,0 +1,32 @@
+package io.livekit.plugin
+
+import androidx.annotation.NonNull
+
+import io.flutter.embedding.engine.plugins.FlutterPlugin
+import io.flutter.plugin.common.MethodCall
+import io.flutter.plugin.common.MethodChannel
+import io.flutter.plugin.common.MethodChannel.MethodCallHandler
+import io.flutter.plugin.common.MethodChannel.Result
+
+/** LiveKitPlugin */
+class LiveKitPlugin: FlutterPlugin, MethodCallHandler {
+  /// The MethodChannel that will the communication between Flutter and native Android
+  ///
+  /// This local reference serves to register the plugin with the Flutter Engine and unregister it
+  /// when the Flutter Engine is detached from the Activity
+  private lateinit var channel : MethodChannel
+
+  override fun onAttachedToEngine(@NonNull flutterPluginBinding: FlutterPlugin.FlutterPluginBinding) {
+    channel = MethodChannel(flutterPluginBinding.binaryMessenger, "livekit_client")
+    channel.setMethodCallHandler(this)
+  }
+
+  override fun onMethodCall(@NonNull call: MethodCall, @NonNull result: Result) {
+    // no-op for now
+    result.notImplemented()
+  }
+
+  override fun onDetachedFromEngine(@NonNull binding: FlutterPlugin.FlutterPluginBinding) {
+    channel.setMethodCallHandler(null)
+  }
+}