tests: infra: extract code to prepare a VMI
tests: infra: extract code to prepare a VMI

Extract the code we need to preparea VMI for
the metrics test in a helper. A future patch
want to use more than one VMI for tests, so this
helper will be handy.

Signed-off-by: Francesco Romani <c7100b580e6017ef67482ace46578cdd2d2e0dfe@redhat.com>

kubevirt/kubevirt,stu-gott/kubevirt,davidvossel/kubevirt,kubevirt/kubevirt,stu-gott/kubevirt,kubevirt/kubevirt,davidvossel/kubevirt,stu-gott/kubevirt,davidvossel/kubevirt,davidvossel/kubevirt,stu-gott/kubevirt,kubevirt/kubevirt