feat: convert Settings to dropdown menu with sub-items

- Convert Settings menu item to dropdown (similar to Contributions)
- Add Global Settings and Roles as sub-items
- Update German translations: 'Global Settings' and 'Roles'

lib/mv_web/components/layouts/navbar.ex

@@ -26,7 +26,19 @@ defmodule MvWeb.Layouts.Navbar do
         <a href="/members" class="btn btn-ghost text-xl">{@club_name}</a>
         <ul class="menu menu-horizontal bg-base-200">
           <li><.link navigate="/members">{gettext("Members")}</.link></li>
-          <li><.link navigate="/settings">{gettext("Settings")}</.link></li>
+          <li>
+            <details>
+              <summary>{gettext("Settings")}</summary>
+              <ul class="bg-base-200 rounded-t-none p-2 z-10 w-48">
+                <li>
+                  <.link navigate="/settings">{gettext("Global Settings")}</.link>
+                </li>
+                <li>
+                  <.link navigate="/admin/roles">{gettext("Roles")}</.link>
+                </li>
+              </ul>
+            </details>
+          </li>
           <li><.link navigate="/users">{gettext("Users")}</.link></li>
           <li>
             <details>