[RFE] Safeguard from defining two hosts with the same data

[kambiz-aghaiepour]

For all versions, I don't believe there is currently anything that would prohibit from having the following conditions met:

quads-cli --host host1.example.com --interface-name em1 --interface-mac <MAC1> --interface-ip <IP1> --interface-port <PORT1>

and

quads-cli --host host2.example.com --interface-name em1 --interface-mac <MAC2> --interface-ip <IP2> --interface-port <PORT2>

The following conditions need to be met:

When defining interface-mac for host2, ensure MAC2 has not been previously associated with another interface (i.e. if MAC2 == MAC1 for all other interfaces across all existing hosts, report an error and disallow defining the interface where the MAC address is currently defined elsewhere.

Ensure that the IP2+PORT2 combination is unique and has not been previously used for another host (two interfaces cannot be connected to the same switch port).