[BREAKING] Improve reusability of gitlab-qa commands

What does this MR do?

• Extract reporting script
• Add default script block for qa base job
• Add ability to run commands with bundle exec prefix (useful when gitlab-qa is installed via Gemfile)
• Use default script block for nightly and dot-com job definitions

Check-list

• Verify the change in all affected pipelines.
  • Test run: https://ops.gitlab.net/gitlab-org/quality/staging/-/jobs/7684273