Build QA image for FOSS repo

What does this MR do and why?

In order to move QA image build and release to Rails repo(s) from omnibus-gitlab, the FOSS repo also needs to be capable of building gitlab-ce-qa image. Moreover, we still have support for running package-and-qa for CE packages, which requires a QA image from FOSS.

Related to omnibus-gitlab#7069 (closed)

Closes: #375330 (closed)

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How to set up and validate locally

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MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.