Refine some details for the github actions update

Set the retention-days variable to 14 days for these artifacts:

• the zloop error logs
• the zloop vdev files
• the compiled modules

Add the abality to re-run some part of the functional testings.
Fix some comments and remove the deleting of the modules artifact.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes #14637