arch_boxes_sync: Create predictable symlinks for latest image files

This is needed so we can provide stable links for libosinfo (used by gnome-boxes, virt-install and virt-manager for easy installation).

---

Drafted so it can be tested with the next release in ~2 days.

roles/arch_boxes_sync/files/arch-boxes-sync.sh

@@ -32,7 +32,17 @@ unzip output.zip
 rm output/*.box{,.*}
 mv output/* "${LATEST_RELEASE_TAG}"
 
+for FILE in "${LATEST_RELEASE_TAG}"/*; do
+  if [[ $FILE == *${LATEST_RELEASE_TAG:1}* ]]; then
+    FILE="${FILE##*/}"
+    ln -s "${FILE}" "${LATEST_RELEASE_TAG}/${FILE//${LATEST_RELEASE_TAG:1}/latest}"
+  fi
+done
+
 mv "${LATEST_RELEASE_TAG}" "${ARCH_BOXES_PATH}/"
+if [[ -d ${ARCH_BOXES_PATH}/latest ]]; then
+  rm "${ARCH_BOXES_PATH}/latest/"*latest*
+fi
 ln -nsf "${LATEST_RELEASE_TAG}" "${ARCH_BOXES_PATH}/latest"
 
 echo "Removing old releases"