bug-1863007: change UPLOAD_TEMPDIR_ORPHANS_CUTOFF to 15 minutes

This drops the cutoff from 60 minutes which kept orphaned files way too
long causing an instance to have disk-full problems for over an hour to
15 minutes which will allow instances to recover more quickly.

15 minutes far exceeds the 6 minute timeout for HTTP request handling,
so files that are still around after 15 minutes are certainly orphaned.

tecken/settings.py

@@ -492,7 +492,7 @@ def filter(self, record):
 )
 UPLOAD_TEMPDIR_ORPHANS_CUTOFF = _config(
     "UPLOAD_TEMPDIR_ORPHANS_CUTOFF",
-    default="60",
+    default="15",
     parser=int,
     doc=(
         "Time in minutes before we consider a file to have been orphaned and should "