Added some logging, and some further documentation

Added logging to the code, and documenting what the code is doing, not
clear with the current code.

docs/courier-to-mailman3.md

@@ -8,3 +8,6 @@ This is our current version trying to communicate between courier and mailman3.
 
 * First change is changing the name to match what I have on the server.
 * Second change is to have the `#!` path hopefully pointing in the right place.
+* Which I screwed up.  I think I was typing in the wrong window.
+  * It's not failing on command line.
+* Still failing, let's get some logging.

source/courier-to-mailman3.py

@@ -1,17 +1,37 @@
-#!/opt/mailman/venv/bin/su python3
+#!/opt/mailman/venv/bin/python3
 #
 # Written by Thomas Schneider <qsuscs@qsuscs.de>
 # This script is placed in public domain.  If this is not applicable, consider
 # it licensed under the CC-0:
 # <https://creativecommons.org/publicdomain/zero/1.0/>
 
+# Command Line Arguments (reverse engineered)
+# $1 LMTP Port
+# $2 ????
+# $3 LMTP Host
+# std_in message text
+
 try:
+    import logging
     import os
     import sys
     import smtplib
 
+    logger = logging.getLogger(__name__)
+
+    logging.basicConfig(filename='~/logs/courier-to-mailman.log', level=logging.INFO)
+
+    FORMAT = '%(asctime)s %(clientip)-15s %(user)-8s %(message)s'
+    logging.basicConfig(format=FORMAT)
+
+    logger.info('Starting Logging')
+
+    # Setup LTMP connection 
     lmtp_host = sys.argv[3] if len(sys.argv) > 3 else 'localhost'
+    logger.info('lmtp_host: %s', lmtp_host)
+    # class smtplib.LMTP(host='', port=LMTP_PORT, local_hostname=None, source_address=None)
     lmtp = smtplib.LMTP(lmtp_host, int(sys.argv[1]))
+    logger.info('lmtp_port: %s', sysv.arg[1])
 
     try:
         # Unfortunately qmail sends to local bare LF for end line, while