axis_record: remove old mp4 files

scripts/axis_record.sh

 #!/bin/bash
 
+# Remove mp4 files that have not been modified for one week
+find . -name \*.mp4 -mtime +7 -delete
+
 ffmpeg \
     -i http://axis-ptz1/mjpg/video.mjpg \
     -t 10:00:00 \