Added Email Alert Functionality

[kunalsz]

This PR adds the email alert functionality as written in the GSOC'25 objectives.

Changes made

• Google's SMTP service has been implemented in the settings. This requires an app password and your email address to send emails
• A new module inside impossible_travel is created alert_email.py to send the emails to a specific address using Django's send_email functionality
• tasks.py has been updated , alert_email has been implemented in set_alert function , now an email is sent when a login anomaly is detected
• tests are created to check if the email is sent correctly or not

Outcomes

• emails are generated successfully when anomaly is detected
• all tests are getting passed

placeholders are left in the place of actual email addresses and app password

Looking forward for your insights and advices !

[kunalsz]

@Lorygold @ManofWax Please review this PR ,your insights will be helpful in improving this PR

[ManofWax]

I appriciate your contribution but I've implemented a new module which allow us implementing different alerting more easily.

I've created an issue with some documentation: #126

Can you reimplement the code using the new module? I'm going to close this PR.