Add Support for Metadata in ElasticSearch Queries(query|suggest)

[abhijeetKumarCompass]

Currently, there is no field in elastic search suggest queries where I can pass metadata to queries. Adding metadata is beneficial in scenarios when query ends up in slow query logs. I can pass details of clientName and work with client to fix their query or access pattern. Further, I can use the metadata to build analytics on slow query logs for further analysis and consumption.

This feature is similar to the analytics tag in elastic app search : https://www.elastic.co/guide/en/app-search/7.8/analytics-tags-guide.html

[dnhatn]

@abhijeetKumarCompass I think the x-opaque-id parameter would be good enough for your problem. Please see: #31539.

[elasticmachine]

Pinging @elastic/es-search (Team:Search)