Description of problem:

IPv6 provisioning requires to have a IPv6 address while creating a host where as we get IPv6 address from the External DHCP server

How reproducible:

Always

Is this issue a regression from an earlier version:

No

Steps to Reproduce:

1. Configure the External DHCP server

2. Configure satellite for provisioning, while creating subnets there is no option for external DHCP

Actual behavior:
While creating the host the IPv6 address is mandatory whereas we don't want that as we get the IPv6 address from the External DHCP server

Expected behavior:
While creating the host the IPv6 address should not be mandatory and a new IPAM mode should be added while creating subnets like External DHCP

Business Impact / Additional info: