[ML] Add flag to auto-close the anomaly detection job when the associated datafeed is stopped

[valeriy42]

Extend the stop datafeeds API to add an optional flag that would close the anomaly detection jobs when the datafeed is stopped. This flag should be deactivated by default to avoid breaking changes to past behavior.

\cc @edsavage , @jgowdyelastic , @davidkyle

[elasticsearchmachine]

Pinging @elastic/ml-core (Team:ML)

[davidkyle]

#74257 (circa 7.14) changed the close job API to automatically stop the associated datafeed when the job was closed. If a user wants to stop the datafeed and close the job in a single API call they can use close job.

That said, there is no harm in adding an option to the stop datafeed API to also close the job it would simply redirect to the close job API where the functionality is already implemented.