build: add print-image-list makefile target

It will be useful to get the list of image names when pushing
containers. This can be used for any scripts that you may need to
write.

Makefile

@@ -24,7 +24,7 @@ PUSH_IMAGES = $(addprefix push-, $(IMAGES))
 
 .PHONY: build sdk-openssl example-test-agent example-resource-agent \
 	images fetch integ-test show-variables cargo-deny tools $(IMAGES) \
-	tag-images $(TAG_IMAGES) push-images $(PUSH_IMAGES)
+	tag-images $(TAG_IMAGES) push-images $(PUSH_IMAGES) print-image-names
 
 export DOCKER_BUILDKIT=1
 export CARGO_HOME = $(TOP)/.cargo
@@ -44,6 +44,20 @@ fetch:
 
 images: fetch $(IMAGES)
 
+# This target prints the image names. It may be useful to write loops over the names of the containers. For example, we
+# might want to check to make sure a repository exists for each image (i.e. maybe a new container has been added to the
+# list since we last pushed, so maybe we need to create a new repository).
+#
+# Example:
+# declare -a arr=($(make print-image-names))
+# for image_name in "${arr[@]}"
+# do
+#   echo "do something with $image_name"
+# done
+print-image-names:
+	$(info $(IMAGES))
+	@echo > /dev/null
+
 # Builds, Lints and Tests the Rust workspace
 build: fetch
 	cargo fmt -- --check