Add jobnum to output file and email subject

[jwkai]

Every output file from this tool has the same name (unique_sequence_data.xlsx), making it easy to misplace files. Moreover, the file is sent via email, and all emails contain identical text, so a user cannot easily search their inbox for specific output files.

The solution is to add a jobnum field to the HTML page, and including this in the output filename and email subject line. A timestamp in the filename could also help.

Output filename is generated here:
https://github.com/cfe-lab/unique-sequence/blob/fb77af9591a87284622f6d1a4478abc9753be8b4/unique_sequence.py#L138
and the email is generated here:
https://github.com/cfe-lab/unique-sequence/blob/fb77af9591a87284622f6d1a4478abc9753be8b4/unique_sequence.py#L189-L191