Add basic alert rules for virt-operator
Add basic alert rules for virt-operator

This PR features only alert rules that can be computed out of metrics
that we already have in the cluster and does not require any changes to
virt-operator itself.

Signed-off-by: Daniel Belenky <1481b7e02b8c8cdcdfab769d02924b7df2a647b6@redhat.com>

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