userportal, webadmin: Prevent snapshot in ppc64

This change disables memory snapshot in the frontend for clusters
with architecture that doesn't support it. The option for create
memory snapshot is now hidden for these cases.
All logic was added in conjunction with the snapshot validation from
the parameter ConfigurationValues.MemorySnapshotSupported.

Change-Id: I148f0a9356086b31e66d4f5dd6eab6afc642cada
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1061774
Signed-off-by: Leonardo Bianconi <leonardo.bianconi@eldorado.org.br>
Signed-off-by: Vitor de Lima <vitor.lima@eldorado.org.br>
Signed-off-by: Gustavo Pedrosa <gustavo.pedrosa@eldorado.org.br>