New recovery_target_timeline=primary option

One-line Summary: This new recovery_target_timeline option would ensure that when rebuilding a replica cluster, the recovery stays in the primary cluster's timeline making it fool proof and avoiding recovery timeline inconsistencies.

Business Use-case: Reduce human interaction when rebuilding replicas where unwanted timelines might have been archived in the repo and speed up recovery.

User impact with the change: New parameter option available 

Implementation details: I would need a subject matter expert to please make this feature a reality 

Estimated Development Time: unknown 

Category: Include the text: Restore, replication