[ADF-2131] Search sorting (#3334)

* sorting configuration

* detect primary sorting and use with document list

* search results sorting

* docs update

* unit tests and code updates

* update code

* update code

* generic sorting picker, test updates

* ability to switch off client side sorting

* update docs for document list

lib/content-services/search/search-sorting-definition.interface.ts

@@ -0,0 +1,24 @@
+/*!
+ * @license
+ * Copyright 2016 Alfresco Software, Ltd.
+ *
+ * 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 SearchSortingDefinition {
+    key: string;
+    label: string;
+    type: string;
+    field: string;
+    ascending: boolean;
+}