Replace http client with opensearch-js client in dev tool console

[zhongnansu]

console plugin doesn't interact with OpenSearch via opensearch-js client. It's just making http requests using Node.js http client. Given that the multiple datasource solution is mostly based on opensearch-js clients, to onboard dev tool console with multiple datasource, we first need to refactor original logic to replace http client with opensearch-js client, and then extend it to use the data source client on demand.

Besides, keeping a unified way for OSD to interact with OpenSearch will benefit us long term. All visualizations/Discover retrieves data from OpenSearch through data plugin. And data plugin under the hood is using opensearch-js client. I don't see the point for OSD dev tool console using http client to interact with OpenSearch.

POC: #3544

Notes:

• To sending request from opensaearch-js client in dev tool console with user input, we can make generic request using client.transport.request

var client = new opensearch.Client();
client.transport.request({
  path: '/_search_with_clusters',
  method: 'PUT'
}).then(console.log.bind(console));

part of #2699

[joshuarrrr]

@zhongnansu Was this completely resolved by #3544? If so, let's close.

[zhongnansu]

resolved but not merged to 2.7 branch yet

[joshuarrrr]

cool - we can close then - it's already in 2.x: #3639