IP Pool management for SSL

At the moment we are rather fortunate in that we have managed to sidestep being tied to ip address management in the current codebase,
but because each SSL certificate can only be associated to one IP address/Port combination on a server we will have to keep track of them.

We have an ip_address field on hosting_server we aren't making use of at the moment, but unfortunately we will need to normalize the information more.

On the server add / edit forms, we will need to provide a mechanism to maintain a list of IP addresses associated to the server. When we do the subsequent server verify we will need to validate that these IP's actually point to the server. This might be complex in that we can only run remote SSH commands and do not have drush available on the remote server.

When the user enables SSH management on the site, we will need to do validation on the current target platform as to wether it has any unclaimed IP addresses available. We will need to do the same validation during migrate and clone commands, to ensure we can actually migrate a site while maintaining SSL.