Create barebones version of the Docker NGINX Unprivileged image

### Is your feature request related to a problem? Please describe

The NGINX Unprivileged images built in this repo require some level of user permissions to run effectively (see #43). 

### Describe the solution you'd like

A version of this image that trades the convenience of the startup scripts to be able to run in more "restricted" environments would be a good value add.
