Link permanently to latest test result

[gerritholl]

Currently, if rymdulf can run anything at all, it always responds with The testing process was executed successfully. See the test results for this pull request here!. The link here always links to the front page. That makes any link that isn't the most recently one posted show the wrong result. Instead, it should use a permanent link. This link will probably ultimately still break as we won't keep the test results forever, but at least it will not point to the wrong page.