feat: Working VoIP calling implementation (Flutter + Android)

Working video and audio calls, as well as android integration

example/integration_test/plugin_integration_test.dart

@@ -0,0 +1,25 @@
+// This is a basic Flutter integration test.
+//
+// Since integration tests run in a full Flutter application, they can interact
+// with the host side of a plugin implementation, unlike Dart unit tests.
+//
+// For more information about Flutter integration tests, please see
+// https://flutter.dev/to/integration-testing
+
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:integration_test/integration_test.dart';
+
+import 'package:liblinphone_flutter/liblinphone_flutter.dart';
+
+void main() {
+  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+
+  testWidgets('getPlatformVersion test', (WidgetTester tester) async {
+    final LiblinphoneFlutter plugin = LiblinphoneFlutter();
+    final String? version = await plugin.getPlatformVersion();
+    // The version string depends on the host platform running the test, so
+    // just assert that some non-empty string is returned.
+    expect(version?.isNotEmpty, true);
+  });
+}