Fix #3116 NIC type selection for vSphere

Provide solution issue [#3116](http://projects.theforeman.org/issues/3116)
Add NIC selection for vSphere and two initial types: E1000 and VMXNET 3

For the future the selection can be optimized to vSphere allowed network interface types, but it is quite complicated to query the API for this result (and not supported by fog at all).

Reviewed by: Dominic Cleal