Make Dockerfiles consistent across the UIs.
Make Dockerfiles consistent across the UIs.

- Set default **AUTH_SERVICE_URL** to labs.
- Simplify structure by combining RUN combines where reasonably possible.
- Remove **HOME_DIR** environment variable to simplify file.
- Update comments.
- Don't `COPY build/docker-npmrc.sh` because it is already copied over.
- Remove unnecessary wrapping braces.
- Ensure `--non-unique` is present in `groupadd` and `useradd` commands.
- Rename **NPM_REGISTRY_URL** to **NPM_REGISTRY**.

TAMULib/LibraryServiceStatusSystemUI,TAMULib/LibraryServiceStatusSystemUI,TAMULib/LibraryServiceStatusSystemUI