Record Testing Farm usage via ATEX using Testing Farm tags

[comps]

Description:

This encodes additional metadata using a generic JSON object called tags in the Testing Farm API: https://api.testing-farm.io/docs#operation/request_a_new_test_v0_1_requests_post

Rationale:

With Packit-based Testing Farm usage, we had at least rough idea of who is running the test by git repo URL, ie.

https://github.com/ggbecker/content
https://github.com/vojtapolasek/content
https://github.com/ComplianceAsCode/content
...

but with ATEX, we only get

https://github.com/RHSecurityCompliance/atex-reserve

because it simply reserves systems from TF, and only then runs tests on them.

This PR adds additional metadata to reserve "requests" (which is what TF calls jobs, basically) to help us at least approximate who is pushing too frequently / using too much of TF resources.

Review Hints:

This might need to be a blind review since I can't change the workflow and test it in the same PR.

[github-actions]

ATEX Test Results

Test artifacts have been submitted to Testing Farm.

Results: View Test Results
Workflow Run: View Workflow Details

This comment was automatically generated by the ATEX workflow.

[comps]

This seems to be working, @ggbecker tested it via https://github.com/ggbecker/content/actions/runs/21402468398 and we can see that the TF requests have the correct metadata, ie. https://api.testing-farm.io/v0.1/requests/f79019ad-ba81-489c-b679-cbb1539602ff :

"github_actor": "ggbecker",
"github_repo": "https://github.com/ggbecker/content"