WIP: run nginx as non-root user

[davidspek]

trafficstars

Summary

Runs the frontend container as non-root.

Test Plan

Checklist

• [ ] If required, I have updated the Plural documentation accordingly.
• [ ] I have added tests to cover my changes.
• [ ] I have added a meaningful title and summary to convey the impact of this PR to a user.
• [ ] I have added relevant labels to this PR to help with categorization for release notes.

[github-actions[bot]]

Visit the preview URL for this PR (updated for commit 0336795):

https://pluralsh--pr420-non-root-frontend-9z2jeyq0.web.app

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[github-actions[bot]]

Visit the preview URL for this PR (updated for commit 734ad84):

https://pluralsh--pr420-non-root-frontend-uygkma7n.web.app

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