Restarting ec2 instance causes a new IP address to be assigned.

It would be useful to assign the ec2 instance an elastic IP, this means that whitelisting the VPN IP to other services will work after a server restart (eg: to save on ec2 costs for irregular use)

Possible to just add a step to the tutorial: `EC2 > Elastic IP > Create > Assign to VPN EC2` or add to the config