userportal, webadmin: Prevent migration on the frontend

This patch transparently disables migration when creating VMs on
architectures that do not support it. This includes pinning the created
VM to a host and forcing the "Do not migrate" resilience policy.

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1057178

Change-Id: I4e6f82dd8906fe8aa3d6c9e28eaf0e155feef51c
Signed-off-by: Vitor de Lima <vitor.lima@eldorado.org.br>