feat(search): enable configuration of the Search component via instrumented config

Signed-off-by: Enrico Alvarenga <enricomalvarenga@gmail.com>

plugins/search/config.d.ts

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export interface Config {
+  app: {
+    /**
+     * Configuration options for the search plugin
+     */
+    search?: {
+      /**
+       * An object representing the initial state configuration for the SearchPage
+       * component. By configuring and modifying the values of the initialState
+       * object attributes, you can customize the initial state of the search component
+       * and define how it behaves when it is first loaded or reset.
+       */
+      initialState?: {
+        /**
+         * A number indicating the maximum number of results to be returned
+         * per page during pagination.
+         *
+         * @visibility frontend
+         */
+        pageLimit?: number;
+      };
+    };
+  };
+}