Final bugs + features

[michellelin1]

• Check backend for security vulnerabilities
• Fix notifications bug (based on Accounts page)
• For Published Schedule - When you try adding a day to the schedule that already exists, the alert that warns them that that day already exists does not show up.
• Add life skills, soft skills, writing, other to subjects
• Search the Published Schedule by date
  • Clear after searching
• Swap student/admin on accounts page
• Add location to top of day planner
• Statistics modal
  • Report actual stats, not row sums
  • Add extra info modal
• Make subject and event type required
• Empty users table in DB
• Swap the email for nodemailer
• Update maintenance doc w/ info architecture + stats route