Prow CI time

[mateusoliveira43]

I was testing a PR using source_ref and source_url in the Pelorus instance, like we do in the Prow end to end (e2e) tests. But I noticed it takes more time (did not time it) than using image_name. And since we do that sometimes during the test run (8 x 4 = 32?) this can make tests longer.

Should we create a test image (one is enough, since they are the same to each exporter), to each PR to accelerate the e2e jobs?