ensure athena is not relying on `en0` network device for host ip

[savar]

in https://github.com/athena-oss/athena/blob/master/lib/shared/functions.os.sh#L603 the _get_host_ip_for_mac is expecting the host IP on device en0 which is not always the same. To improve this situation we should at least (thinking of IPv4/v6) go through en* and take the first private IPv4 address we find

[bassco]

@Savar see PR #46 for a possible solution