userportal: UserVmManager cannot edit Custom properties

This patch hides the custom properties side tab on the User portal, when
creating a new VM and when editing one. Also removing the Custom
Properties panel from Run-Once, in the user portal.

Change-Id: Icf8e0929f6969b5ca1fe592a960d2e91c83046b1
Bug-Url: https://bugzilla.redhat.com/911091
Signed-off-by: Oved Ourfali <oourfali@redhat.com>