Add initial page setting. Close #240

lib/pages/main_page.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:venera/foundation/appdata.dart';
 import 'package:venera/pages/categories_page.dart';
 import 'package:venera/pages/search_page.dart';
 import 'package:venera/pages/settings/settings_page.dart';
@@ -39,6 +40,7 @@ class _MainPageState extends State<MainPage> {
     _observer = NaviObserver();
     _navigatorKey = GlobalKey();
     App.mainNavigatorKey = _navigatorKey;
+    index = int.tryParse(appdata.settings['initialPage'].toString()) ?? 0;
     super.initState();
   }
 
@@ -60,6 +62,7 @@ class _MainPageState extends State<MainPage> {
   @override
   Widget build(BuildContext context) {
     return NaviPane(
+      initialPage: index,
       observer: _observer,
       navigatorKey: _navigatorKey!,
       paneItems: [

lib/pages/settings/explore_settings.dart

@@ -80,6 +80,16 @@ class _ExploreSettingsState extends State<ExploreSettings> {
             'japanese': "Japanese",
           },
         ).toSliver(),
+        SelectSetting(
+          title: "Initial Page".tl,
+          settingKey: "initialPage",
+          optionTranslation: {
+            '0': "Home Page".tl,
+            '1': "Favorites Page".tl,
+            '2': "Explore Page".tl,
+            '3': "Categories Page".tl,
+          },
+        ).toSliver(),
       ],
     );
   }