refactor(frontend): 🔥 rewrite backup UI for new page base components

Removed old split code and used the composition api to to re-write the import/export functionality of mealie.

frontend/layouts/admin.vue

@@ -122,6 +122,11 @@ export default defineComponent({
           to: "/admin/migrations",
           title: this.$t("sidebar.migrations"),
         },
+        {
+          icon: this.$globals.icons.database,
+          to: "/admin/backups",
+          title: this.$t("sidebar.backups"),
+        },
       ],
       bottomLinks: [
         {