offline-template: replace "index.html" with something more useful

We're showing the "GitLab test job index" instead of an index to the logs of the failed test.

example: https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-internal-contributors/-/jobs/9017472305

  x86_64 - ❌ LTP lite - bare_metal (ID=redhat:1651860955-x86_64-kernel_upt_6):
    Logs:
        - main-output.log: https://artifacts.internal.cki-project.org/arr-cki-prod-internal-artifacts/internal-artifacts/1651860955/test_x86_64/9017171720/artifacts/run.done.01/job.01/recipes/18001814/tasks/7/logs/taskout.log
        - index.html: https://artifacts.internal.cki-project.org/arr-cki-prod-internal-artifacts/internal-artifacts/1651860955/test_x86_64/9017171720/index.html

1. It would be better if in this case the index.html would point directly to https://artifacts.internal.cki-project.org/arr-cki-prod-internal-artifacts/internal-artifacts%2F1651860955%2Ftest_x86_64%2F9017171720%2Fartifacts%2Frun.done.01%2Fjob.01%2Findex.html
2. Open https://artifacts.internal.cki-project.org/arr-cki-prod-internal-artifacts/internal-artifacts%2F1651860955%2Ftest_x86_64%2F9017171720%2Fartifacts%2Frun.done.01%2Fjob.01%2Findex.html

• The link for the logs in the page don't work...

Jira: CKI-6788