make deployment domain agnostic

[mjsobrep]

There are a bunch of places that should be pulling the domain from a config:

• https://github.com/Rehab-Robotics-Lab/LilFloSystem/blob/b07d828ef5a8b1902c0cfa2881900a3c671d0f00/init-letsencrypt.sh#L8
• https://github.com/Rehab-Robotics-Lab/LilFloSystem/blob/b07d828ef5a8b1902c0cfa2881900a3c671d0f00/init-letsencrypt-turn.sh#L8
• https://github.com/Rehab-Robotics-Lab/LilFloSystem/blob/b07d828ef5a8b1902c0cfa2881900a3c671d0f00/flo_web/nginx-prod.conf#L55

Other variables that should come from config:

• https://github.com/Rehab-Robotics-Lab/LilFloSystem/blob/b07d828ef5a8b1902c0cfa2881900a3c671d0f00/init-letsencrypt.sh#L11
• https://github.com/Rehab-Robotics-Lab/LilFloSystem/blob/b07d828ef5a8b1902c0cfa2881900a3c671d0f00/init-letsencrypt-turn.sh#L11

Notes:

• the letencrypt keys will be based off of the first domain name: https://github.com/Rehab-Robotics-Lab/LilFloSystem/blob/b07d828ef5a8b1902c0cfa2881900a3c671d0f00/init-letsencrypt.sh#L31
• I'm not sure if these needs to change. I think because there is only one route on 443, it is ok: https://github.com/Rehab-Robotics-Lab/LilFloSystem/blob/b07d828ef5a8b1902c0cfa2881900a3c671d0f00/flo_web/nginx-prod.conf#L53