Consider pod image in duplicates strategy

This increases the specificity of the RemoveDuplicates strategy by
removing pods which not only have the same owner, but who also
must have the same list of container images. This also adds a
parameter, `ExcludeOwnerKinds` to the RemoveDuplicates strategy
which accepts a list of Kinds. If a pod has any of these Kinds as
an owner, that pod is not considered for eviction.

pkg/api/types.go

@@ -50,6 +50,7 @@ type StrategyParameters struct {
 	NodeAffinityType                  []string
 	PodsHavingTooManyRestarts         *PodsHavingTooManyRestarts
 	MaxPodLifeTimeSeconds             *uint
+	RemoveDuplicates                  *RemoveDuplicates
 }
 
 type Percentage float64
@@ -65,3 +66,7 @@ type PodsHavingTooManyRestarts struct {
 	PodRestartThreshold     int32
 	IncludingInitContainers bool
 }
+
+type RemoveDuplicates struct {
+	ExcludeOwnerKinds []string
+}