Use temporary file for kind-load target

This simplified logic should work on both podman and docker, removing
our need to have distinct ways of handling the image loading.

Makefile

@@ -154,15 +154,10 @@ e2e-coverage:
 
 .PHONY: kind-load
 kind-load: $(KIND) #EXHELP Loads the currently constructed image onto the cluster.
-ifeq ($(CONTAINER_RUNTIME),podman)
-	@echo "Using Podman"
-	podman save $(IMG) -o $(IMG).tar
-	$(KIND) load image-archive $(IMG).tar --name $(KIND_CLUSTER_NAME)
-	rm $(IMG).tar
-else
-	@echo "Using Docker"
-	$(KIND) load docker-image $(IMG) --name $(KIND_CLUSTER_NAME)
-endif
+	TMP_FILE=$(shell mktemp -t operator-controller-image-archive-XXXX.tar) ;\
+	$(CONTAINER_RUNTIME) save $(IMG) -o $$TMP_FILE ;\
+	$(KIND) load image-archive $$TMP_FILE --name $(KIND_CLUSTER_NAME) ;\
+	rm $$TMP_FILE
 
 kind-deploy: export MANIFEST="./operator-controller.yaml"
 kind-deploy: manifests $(KUSTOMIZE) #EXHELP Install controller and dependencies onto the kind cluster.