Move date-checking logic to utils and unit test it

app/utils.py

@@ -676,3 +676,9 @@ def format_thousands(value):
     if value is None:
         return ''
     return value
+
+
+def is_less_than_90_days_ago(date_from_db):
+    return (datetime.utcnow() - datetime.strptime(
+        date_from_db, '%a, %d %b %Y %X %Z'
+    )).days < 90