Cleanup settings page(s)

- New separate directory
- Separate view for About information

lib/settings/settings.dart

@@ -0,0 +1,62 @@
+import 'package:InvenTree/settings/about.dart';
+import 'package:InvenTree/settings/login.dart';
+
+import 'package:flutter/material.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+import 'package:InvenTree/api.dart';
+import 'login.dart';
+
+import 'package:package_info/package_info.dart';
+
+class InvenTreeSettingsWidget extends StatefulWidget {
+  // InvenTree settings view
+
+  @override
+  _InvenTreeSettingsState createState() => _InvenTreeSettingsState();
+
+}
+
+
+class _InvenTreeSettingsState extends State<InvenTreeSettingsWidget> {
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text("InvenTree Settings"),
+      ),
+      body: Center(
+        child: ListView(
+          children: <Widget>[
+            ListTile(
+                title: Text("Server Settings"),
+                subtitle: Text("Configure server and login settings"),
+                onTap: _editServerSettings,
+            ),
+            Divider(),
+            ListTile(
+              title: Text("About"),
+              subtitle: Text("App details"),
+              onTap: _about,
+            ),
+          ],
+        )
+      )
+    );
+  }
+
+  void _editServerSettings() async {
+
+    var prefs = await SharedPreferences.getInstance();
+
+    Navigator.push(context, MaterialPageRoute(builder: (context) => InvenTreeLoginSettingsWidget(prefs)));
+  }
+
+  void _about() async {
+
+    PackageInfo.fromPlatform().then((PackageInfo info) {
+      Navigator.push(context,
+          MaterialPageRoute(builder: (context) => InvenTreeAboutWidget(info)));
+    });
+  }
+}