Automate RhMatcherWorkflow execution to eliminate manual intervention in advisory generation pipeline

[rockythorn]

Adds Kubernetes CronJob that runs RhMatcherWorkflow every 6 hours, completing the final manual step in the Rocky Linux advisory automation. Follows the same pattern as the existing apollo-rhworker PollRHCSAFAdvisoriesWorkflow CronJob.

[elguero]

Looks sane to me.

Mustafa or Neil should double check.

[NeilHanlon]

This looks great overall, thanks very much @rockythorn ! Follows established patterns, best practices, and sidecar management integration pain I ran into.

A couple operational suggestions to discuss/work in (independent of this PR):

• Consider adding concurrencyPolicy: Forbid to the CronJob spec -- since the wf has a 12 hour timeout per product, if a job takes >6h we may get overlapping executions leading to a resource exhaustion upstream somewhere (database/cpu)
• Given the 12 hour activity timeout, we might want to monitor/profile the actual runtime and consider if the schedule needs adjustment. We can watch this post-deployment.
• Commit message says "every 4 hours" but the code says every 6. Minor nit for posterity so I can't be accused of missing anything ;)

LGTM! 🚀