Refactor to new CHT pipeline pattern
Closes: https://dccscr.dsop.io/dsop/gitlab/gitlab/gitlab-task-runner/issues/3
- Removes gitlab versioned folders prior to 12.8
- Unwraps the 12.8 folder into the root
- Removes the prebuild.sh script in favor of download.json
- Drops the build script for now
- Update prepare script to use local downloaded artifact
Edited by DJ Mountney