#27 add basic auth for dev/test environments

[adgud]

List of changes

This adds a basic auth prompt on dev and test environments.

The authorization user/password hash is stored in GH Actions secret called $NGINX_BASIC_AUTH.

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works

Screenshots of change (for FE)