Implement send mail reporting

Implementation of own module which enables a reporting via mail.

First steps would be to implement mailing functionallity as own Class
Then "design" a report - mail with all graphics that have been generated in the analytics notebook.

Look for existing analytics notebook code that generates graphics. Start by creating a new mail module class, likely using Python's smtplib or a library like yagmail. The report mail needs to attach generated graphics; check how and where these graphics are saved. Test sending a mail with attachments locally first.

索引モデルが issue の本文から書いたものです。