Replace trigger jobs with branch build jobs

What does this MR do?

Trigger jobs and their branch build counterparts essentially do the same thing. Now that we have the ability to run any pipeline type on any mirror, let's consolidate them.

Changes

1. Replace Trigger: jobs with branch build counterparts
2. Tag QA image using version tag instead of commit SHA. As far as I can tell, no one actually uses the commit SHA tag, and it was added in !4259 (merged) to fix #5369 (closed), where the requirement was the presence of a docker image - it didn't matter what the tag was.

To note

1. The jobs that run in dev.gitlab.org use a dedicated runner and cache bucket for them. So, having the same job definition in .com pipelines won't pollute the cache.

Related issues

#7187 (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