Headless and tailless configurations (primary/secondary switch)

Perform primary to secondary server switch on outages or issues:

• Pheix project headless and tailless configurations: 3e46ac4f;
• Nginx on Trappist-1 server with a load-balancing configuration both to Ala-Archa and Southern-Deadend-5 —  ???  hmm, why do we need headless and tailless configurations if we are balancing via Nginx between standalone instances on different servers.