Files uploaded by the user when creating/executing a synchronous job were never
deleted after the job execution.

The same problem applied for the tables already uploaded in the database (in
`TAP_UPLOAD`) when an error occurred before the end of the UPLOAD process.

Now, in case of error when uploading one or more files, or in case of success of
the job, all uploaded files and their corresponding database tables are deleted
after the end of the job.