[PoC]Enforce project size limits on docker registry

What does this MR do?

This is a PoC showing how to enforce project size limits on docker registry.

$ docker push 127.0.0.1:5000/work/limits/alpine:3.8
The push refers to repository [127.0.0.1:5000/work/limits/alpine]
df64d3292fd6: Preparing
denied: The size of this repository (2 MB) exceeds the limit of 1 MB by 990 KB. You won't be able to push new code to this project. Please contact your GitLab administrator for more information.

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Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
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• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• EE specific content should be in the top level /ee folder
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• Security reports checked/validated by reviewer