[Feature Request] Create the UBI indexes in a friendlier manner

[jzonthemtn]

Is your feature request related to a problem? Please describe

In #13545, the UBI indexes are only created when a search request containing a ubi section in ext is received. The ubi_events and ubi_queries indexes are then created. This requires the user to make a query to create the indexes which is not ideal, and also requires checking to see if those indexes exist for each UBI-enabeld search request.

Describe the solution you'd like

There should be another mechanism for creating the ubi_queries and ubi_events indexes, such as a new REST endpoint to initialize UBI which creates the indexes.

Additional context

Related to the UBI RFC #12084 and UBI initial code in #13545.

This issue can be assigned to myself.

[andrross]

[Triage - attendees 1 2 3 4]
@jzonthemtn Thanks for filing.

[jzonthemtn]

Closing this RFC because the initial implementation is now available at https://github.com/opensearch-project/user-behavior-insights and new issues can be created there.