Simplify usage of custom justfile targets

scripts/util.py

@@ -0,0 +1,10 @@
+from pathlib import Path
+
+
+def get_latest_newsletter_number():
+    # Find the number of the latest newsletter
+    destination_path = Path(f"./content/newsletter")
+    p = destination_path.glob("craft-letter-*.md")
+    files = [x for x in p if x.is_file()]
+    letter_number = len(files)
+    return letter_number