Add package-and-qa jobs for TRIGGER_CACHE_UPDATE_PIPELINE

What does this MR do?

There is a scheduled pipeline in gitlab-org/gitlab project that runs every 2 hours. The purpose of this pipeline is to ensure master branch is green with a full test run (including E2E tests), clean up stale review apps, caching the bulky gitlab-org/gitlab repo for CI and updating all caches. For the purpose of running E2E tests, it makes use of the package-and-qa job, which in turn runs a triggered pipeline in omnibus-gitlab-mirror. Now, for the cache update part, this triggered pipeline also includes the update-trigger-package-cache job in omnibus-gitlab. This job essentially updates the build cache of omnibus-gitlab so that subsequent package-and-qa runs from gitlab-org/gitlab MRs can use this cache.

As part of the refactor in !6228 (diffs), this pipeline is named TRIGGER_CACHE_UPDATE_PIPELINE. However, while we remembered to assign the update-trigger-package-cache job to this pipeline, we missed adding the other ones - building a package,building a docker image, and triggering a qa run for E2E tests. 🤦

This MR fixes that.

Related issues

Closes #6964 (closed)

#7188 (closed)

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion

Required

• Merge Request Title, and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• Pipeline is green on dev.gitlab.org if the change is touching anything besides documentation or internal cookbooks
• trigger-package has a green pipeline running against latest commit

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for the GitLab Chart opened