test: add coarse test for unused media files

Signed-off-by: David Karlsson <35727626+dvdksn@users.noreply.github.com>

scripts/test_unused_media.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env sh
+
+# Find all media files {svg,png,webp,mp4,jpg,jpeg} in {content,static}
+MEDIA=$(fd . -e "svg" -e "png" -e "webp" -e "mp4" -e "jpg" -e "jpeg" ./content ./static)
+TEMPFILE=$(mktemp)
+
+for file in $MEDIA; do
+  rg -q "$(basename $file)"
+  if [ $? -ne 0 ]; then
+    echo "$file" >> "$TEMPFILE"
+  fi
+done
+
+UNUSED_FILES=$(< $TEMPFILE)
+rm $TEMPFILE
+
+if [ -z "$UNUSED_FILES" ]; then
+  exit 0
+else
+  echo "$(echo "$UNUSED_FILES" | wc -l) unused media files. Please remove them."
+  printf "%s\n" ${UNUSED_FILES[@]}
+  exit 1
+fi