assign hostnames to IPs

[Markus Petzsch <markus@…>]

In order to grant resellers access to openVCP and enabling them to create their own vservers, it'd be nice to assign a hostname to an IP so that the real RDNS name would be associated to each vserver.

Currently it's freely choosable for each vserver, which can lead to fantasy hostnames not releated to the PTR record of the IP beeing used.

When setting up IPs for a node i'd like to be able to preset the hostnames.