Issue search support elasticsearch (#9428)

* Issue search support elasticsearch

* Fix lint

* Add indexer name on app.ini

* add a warnning on SearchIssuesByKeyword

* improve code

vendor/github.com/olivere/elastic/v7/search_queries_wrapper.go

@@ -0,0 +1,28 @@
+// Copyright 2012-present Oliver Eilhard. All rights reserved.
+// Use of this source code is governed by a MIT-license.
+// See http://olivere.mit-license.org/license.txt for details.
+
+package elastic
+
+// WrapperQuery accepts any other query as base64 encoded string.
+//
+// For details, see
+// https://www.elastic.co/guide/en/elasticsearch/reference/7.0/query-dsl-wrapper-query.html.
+type WrapperQuery struct {
+	source string
+}
+
+// NewWrapperQuery creates and initializes a new WrapperQuery.
+func NewWrapperQuery(source string) *WrapperQuery {
+	return &WrapperQuery{source: source}
+}
+
+// Source returns JSON for the query.
+func (q *WrapperQuery) Source() (interface{}, error) {
+	// {"wrapper":{"query":"..."}}
+	source := make(map[string]interface{})
+	tq := make(map[string]interface{})
+	source["wrapper"] = tq
+	tq["query"] = q.source
+	return source, nil
+}