Topology: add ipv4/ipv6 selection to Subnet create page
Topology: add ipv4/ipv6 selection to Subnet create page

https://bugzilla.redhat.com/show_bug.cgi?id=1394286
(transferred from ManageIQ/manageiq@bd4d1e62fdae3dff24968009efa0b3b12cf60232)

ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic