Fix no-status bug, add file organizaiton

Fix no-status bug, add file organizaiton

This commit introuduces multiple fixes and improvements:
* The check for recording status complete could fail if there was no
status for a given recording, which the Zoom API apparently does.  A
check for the non-existence of the 'status' key was added.
* The script downloaded all types as MP4 files, which is a mess if there
are CC, M4A, VTT, etc, to also download.  File type detection was added.
* The script organizes all related recordings in subdirectories by
meeting ID.