Fix broken step-runner release

Changes

Fixes the broken release (see https://gitlab.com/gitlab-org/step-runner/-/jobs/12369793712)

Specifically,

• Remove commented out includes in .gitlab-ci.yml
• Update jobs to use version of Docker defined in variables.gitlab-ci.yml
• Fixes release by changing the deploy to:
  • Stop depending on binaries
  • Stop tagging binary images that have been removed
  • Stop using the step runner legacy image
  • Update the release description to stop mentioning artifacts that don't exist

Tests

Verified works as expected using a modified fork https://gitlab.com/cam_swords/step-runner-release-2/-/pipelines/2204612257.

Related

Relates to issue Remove distribution image building from pipeline (#331 - closed)