[#10] Fix incorrect TLS certificate location for panel.minersrealm.net

Associated issue: #10 (closed).

Change the location of the TLS certificate from /etc/letsencrypt/live/minersrealm.net/fullchain.pem to /etc/letsencrypt/live/panel.minersrealm.net/fullchain.pem.

This fixes the error: cannot load certificate "/etc/letsencrypt/live/minersrealm.net/fullchain.pem".

Closes #10 (closed).