Allow retriggering OpenScanHub scan via comment

[mfocko]

Description

As it has been brought up on Thursday on internal Slack, it is not possible to retrigger explicitly only the OpenScanHub' scan. We should allow re-triggering of just a scan via comment without an additional Copr build.

MR in question: https://gitlab.com/CentOS/automotive/src/automotive-image-builder/-/merge_requests/228

• failed OSH scan blocked the merging process
• failure was caused by a network / infra flake
• it wasn't clear that retriggering the Copr build also retriggers the OSH scan

Benefit

• saving resources of the Copr infra, since it will allow re-triggering scan without additional Copr build
• better UX, since it allows users to retrigger just a scan and do it explicitly (not indirectly as the current workaround of re-triggering a Copr build to trigger the OSH scan again)

Importance

No response

What is the impacted category (job)?

OpenScanHub

Workaround

• There is an existing workaround that can be used until this feature is implemented.

Participation

• I am willing to submit a pull request for this issue. (Packit team is happy to help!)