Add Settings Tab to SideBarView

This commit augments the `SideBarView` by introducing a new `IconButton` that represents a tab for the newly created `SettingsView`. This enhancement allows users to navigate to the settings page directly from the sidebar, improving accessibility to app configuration options.

Key Changes:
- A new `IconButton` with a settings icon has been added to the sidebar’s `Column` widget.
- Selecting the settings tab updates the `selectedViewNotifier.value` to `'SettingsView'`, indicating the user's intent to navigate to the settings page.
- Visual feedback is provided by altering the color of the settings icon based on whether the settings tab is currently selected.

This addition ensures seamless integration of the `SettingsView` into the existing navigation structure, enabling users to easily configure app settings.

frontend/lib/views/side_bar/side_bar_view.dart

@@ -35,11 +35,20 @@ class SideBarView extends StatelessWidget {
                     color: selectedView == 'SkillTreeView'
                         ? Colors.blue
                         : Colors.black,
-                    icon: const Icon(Icons.emoji_events), // trophy icon
+                    icon: const Icon(Icons.emoji_events),
                     onPressed: skillTreeViewModel.isBenchmarkRunning
                         ? null
                         : () => selectedViewNotifier.value = 'SkillTreeView',
                   ),
+                  IconButton(
+                    splashRadius: 0.1,
+                    color: selectedView == 'SettingsView'
+                        ? Colors.blue
+                        : Colors.black,
+                    icon: const Icon(Icons.settings),
+                    onPressed: () =>
+                        selectedViewNotifier.value = 'SettingsView',
+                  ),
                 ],
               ),
             );