Allow to configure the public-ip with a role variable instead of ansible_host

[Nuttymoon]

Currently, the public-ip property is generated using the special ansible_host variable. This is fine if the node has its own public IP, but it is frequent to run nodes as VMs sitting behind a bridge interface or a proxy. In this case, the ansible_host variable used to connect through SSH might be different than the public IP.

I suggest adding a avalanchego_public_ip: {{ ansible_host }} to the avalanche_node role to allow easier configuration.