refactor(example): package specific examples instead of a single example

packages/fl_query/example/lib/main.dart

@@ -0,0 +1,64 @@
+import 'package:fl_query_example/components/basic_mutation.dart';
+import 'package:fl_query_example/components/basic_query.dart';
+import 'package:fl_query_example/components/lazy_query.dart';
+import 'package:fl_query_example/components/mutation_variable_key.dart';
+import 'package:fl_query_example/components/query_external_data.dart';
+import 'package:fl_query_example/components/query_variable_key.dart';
+import 'package:fl_query/fl_query.dart';
+import 'package:flutter/material.dart';
+
+void main() {
+  runApp(const MyApp());
+}
+
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return QueryBowlScope(
+      child: MaterialApp(
+        // showPerformanceOverlay: true,
+        title: 'Flutter Demo',
+        theme: ThemeData(
+          useMaterial3: true,
+          primarySwatch: Colors.blue,
+        ),
+        home: const MyHomePage(),
+      ),
+    );
+  }
+}
+
+class MyHomePage extends StatefulWidget {
+  const MyHomePage({Key? key}) : super(key: key);
+
+  @override
+  State<MyHomePage> createState() => _MyHomePageState();
+}
+
+class _MyHomePageState extends State<MyHomePage> with WidgetsBindingObserver {
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text("Fl Query Example"),
+      ),
+      body: SingleChildScrollView(
+          child: Padding(
+        padding: const EdgeInsets.all(8.0),
+        child: Column(
+          children: const [
+            BasicQueryExample(),
+            QueryExternalDataExample(),
+            LazyQueryExample(),
+            QueryVariableKeyExample(),
+            Divider(),
+            BasicMutationExample(),
+            MutationVariableKeyExample(),
+          ],
+        ),
+      )),
+    );
+  }
+}