Improve submission logging

Would be nice to improve the submission logging of the Post2API scripts and get some kind of log file with unsuccessful submits that gets reported (emailed) once its growing. Another nice feature would be to once in a while take this log file and make some kind of script that automatically tries to repost this data.

Since August 2024 both the SQL database and the preprocessing/posting server are very stable but you never know what might pop up in the future and this could give a head start. This could also help in the future if somehow any of the three sites is temporarily down or has no stable connection with WURnet.