Add roles routes to backend and frontend; implement routing and UI components for admin roles management

frontend/src/router/index.js

@@ -19,6 +19,7 @@ import Holidays from '../views/Holidays.vue'
 import Profile from '../views/Profile.vue'
 import PasswordChange from '../views/PasswordChange.vue'
 import Timewish from '../views/Timewish.vue'
+import Roles from '../views/Roles.vue'
 
 const router = createRouter({
   history: createWebHistory(import.meta.env.BASE_URL),
@@ -101,6 +102,12 @@ const router = createRouter({
       component: Holidays,
       meta: { requiresAuth: true, requiresAdmin: true }
     },
+    {
+      path: '/admin/roles',
+      name: 'admin-roles',
+      component: Roles,
+      meta: { requiresAuth: true, requiresAdmin: true }
+    },
     {
       path: '/settings/profile',
       name: 'settings-profile',