[BitSail][Connector]Elasticsearch connector refactor (#492)

[BitSail][Connector]Support Elasticsearch Connector

bitsail-connectors/connector-elasticsearch/src/main/java/com/bytedance/bitsail/connector/elasticsearch/constants/Elasticsearchs.java

@@ -0,0 +1,22 @@
+/*
+ *       Copyright 2022-2023 Bytedance Ltd. and/or its affiliates.
+ *
+ *       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.
+ */
+
+package com.bytedance.bitsail.connector.elasticsearch.constants;
+
+public class Elasticsearchs {
+
+  public static final String COMMA = ",";
+}