chore: import upstream snapshot with attribution

ui/template/opensearch.xml

@@ -0,0 +1,29 @@
+<!--
+
+    Licensed to the Apache Software Foundation (ASF) under one
+    or more contributor license agreements.  See the NOTICE file
+    distributed with this work for additional information
+    regarding copyright ownership.  The ASF licenses this file
+    to you 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.
+
+-->
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/">
+  <ShortName>{{$.general.Name}}</ShortName>
+  {{if $.general.Description}}
+  <Description>{{$.general.Description}}</Description>
+  {{end}}
+  <InputEncoding>UTF-8</InputEncoding>
+  <Image width="16" height="16" type="image/x-icon">{{$.favicon}}</Image>
+  <Url type="text/html" method="get" template="{{$.general.SiteUrl}}/search?q={searchTerms}"/>
+</OpenSearchDescription>