This commit adds support for passing IPv6 Addresses and/or Subnets as
Secondary IPs.
This is groundwork for CLOUDSTACK-9853 where IPv6 Subnets have to be
allowed in the Security Groups of Instances to we can add DHCPv6
Prefix Delegation.
Use ; instead of : for separating addresses, otherwise it would cause
problems with IPv6 Addresses.
Signed-off-by: Wido den Hollander <wido@widodh.nl>