Resolve "Add ApplicationSettings widgets"

Closes #6 (closed)

lib/settings/application_settings_form.dart

+import 'package:flutter/material.dart';
+
+import 'package:flutter_custom_toolbox/flutter_toolbox.dart';
+import 'package:flutter_custom_toolbox/settings/application_settings_theme_card.dart';
+
+class ApplicationSettingsForm extends StatefulWidget {
+  const ApplicationSettingsForm({super.key});
+
+  @override
+  State<ApplicationSettingsForm> createState() => _ApplicationSettingsFormState();
+}
+
+class _ApplicationSettingsFormState extends State<ApplicationSettingsForm> {
+  @override
+  void dispose() {
+    super.dispose();
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      mainAxisAlignment: MainAxisAlignment.start,
+      crossAxisAlignment: CrossAxisAlignment.start,
+      mainAxisSize: MainAxisSize.max,
+      children: <Widget>[
+        // Light/dark theme
+        Row(
+          mainAxisAlignment: MainAxisAlignment.spaceBetween,
+          crossAxisAlignment: CrossAxisAlignment.center,
+          children: <Widget>[
+            const Text('settings_label_theme').tr(),
+            const Row(
+              mainAxisAlignment: MainAxisAlignment.end,
+              crossAxisAlignment: CrossAxisAlignment.center,
+              children: [
+                ApplicationSettingsThemeModeCard(
+                  mode: ThemeMode.system,
+                  icon: UniconsLine.cog,
+                ),
+                ApplicationSettingsThemeModeCard(
+                  mode: ThemeMode.light,
+                  icon: UniconsLine.sun,
+                ),
+                ApplicationSettingsThemeModeCard(
+                  mode: ThemeMode.dark,
+                  icon: UniconsLine.moon,
+                )
+              ],
+            ),
+          ],
+        ),
+
+        const SizedBox(height: 16),
+      ],
+    );
+  }
+}