add page for aur search

install aur package by button click

frontend/lib/api/aur.dart

@@ -0,0 +1,15 @@
+import 'package:aurcache/models/aur_package.dart';
+
+import 'api_client.dart';
+
+extension AURApi on ApiClient {
+  Future<List<AurPackage>> getAurPackages(String query) async {
+    final resp = await getRawClient().get("/search?query=$query");
+
+    final responseObject = resp.data as List;
+    final List<AurPackage> packages = responseObject
+        .map((e) => AurPackage.fromJson(e))
+        .toList(growable: false);
+    return packages;
+  }
+}