Improve regex to detect stacktraces in qa failure issues and mention the job URL when creating failure issues

• 1957cb25 2020-11-13 | Improve the regex to detect stack traces in failure issues [Rémy Coutable]
• 56afd6b0 2020-11-13 | Mention the job URL when creating failure issues [Rémy Coutable]
• 34973374 2020-11-18 | Only post to Slack when in a monitored E2E pipeline [Rémy Coutable]
• b723c3f0 2020-11-18 | Add 'found:*' label to E2E failure issues [Rémy Coutable]
• 4b33dd68 2020-11-17 | Use a test project to create E2E failure issues [Rémy Coutable]

Try to improve https://gitlab.com/gitlab-org/quality/team-tasks/-/issues/731 and closes https://gitlab.com/gitlab-org/quality/team-tasks/-/issues/725.