feat: get images (#135)

Repository specific list of images.
Used by CVE scanning workflows and can be used to collect images URL for airgapped setup.

Summary of changes:
- Added script that retrieves image managed by charm.

tools/get-images-1.7-stable.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+#
+# This script returns list of container images that are managed by this charm and/or its workload
+#
+# static list
+STATIC_IMAGE_LIST=(
+)
+# dynamic list
+git checkout origin/track/1.7
+IMAGE_LIST=()
+IMAGE_LIST+=($(find -type f -name metadata.yaml -exec yq '.resources | to_entries | .[] | .value | ."upstream-source"' {} \;))
+
+printf "%s\n" "${STATIC_IMAGE_LIST[@]}"
+printf "%s\n" "${IMAGE_LIST[@]}"