Check for duplicate hostnames through colonizer deployment

[ramkrsna]

Currently we are not checking for duplicate hostnames when deploying through colonizer. we check if the host IPs are duplicates but not the hostnames. Hence the deployment proceeds with duplicate hostnames and fails during volume creation as bricks from different nodes have same brick path as hostnames are same, this leading to an inconsistent environment. We also need to check for a Valid IP address.

• RFE
• This is a request originating from https://bugzilla.redhat.com/show_bug.cgi?id=1569912