Make IPv6 address inselectable when * is set for IPv4 address for vhost.

Summary

When creating a new site and selecting "*" for IPv4 address, you can still select a IPv6 address. This option should be blurred out (and set to none), and maybe we should show a text like "Vhost is listening on all server addresses" to the IPv6 field.

References

https://www.howtoforge.com/community/threads/2-ipv6-addresses-which-one.86944/