Implement Email Notifications

[fabian-emilius]

• Student should be notified if application is submitted
• Student should be notified if application is declined
• Student and instructor should be notified if application is accepted
• Student should receive a list with things to do after being accepted
• Reviewers should receive a reminder email if applications were not reviewed for 2 weeks
• Students should receive changes on their thesis (new comments, new state etc)
• Students should receive invitations for thesis presentations so that they can watch others
• Instructors should receive updates by student on thesis page