Add cost-based vacuum delay time to progress views.

Add cost-based vacuum delay time to progress views.

This commit adds the amount of time spent sleeping due to
cost-based delay to the pg_stat_progress_vacuum and
pg_stat_progress_analyze system views.  A new configuration
parameter named track_cost_delay_timing, which is off by default,
controls whether this information is gathered.  For vacuum, the
reported value includes the sleep time of any associated parallel
workers.  However, parallel workers only report their sleep time
once per second to avoid overloading the leader process.

Bumps catversion.

Author: Bertrand Drouvot <[email protected]>
Co-authored-by: Nathan Bossart <[email protected]>
Reviewed-by: Sami Imseih <[email protected]>
Reviewed-by: Robert Haas <[email protected]>
Reviewed-by: Masahiko Sawada <[email protected]>
Reviewed-by: Masahiro Ikeda <[email protected]>
Reviewed-by: Dilip Kumar <[email protected]>
Reviewed-by: Sergei Kornilov <[email protected]>
Discussion: https://postgr.es/m/ZmaXmWDL829fzAVX%40ip-10-97-1-34.eu-west-3.compute.internal