Change

archive_cleanup_command
promote_trigger_file
recovery_end_command
recovery_min_apply_delay

from PGC_POSTMASTER to PGC_SIGHUP.  This did not require any further
changes.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://www.postgresql.org/message-id/flat/ca28011a-cfaa-565c-d622-c1907c33ecf7%402ndquadrant.com