Frontend: Authentication Check & Restricting User Views

[ceciliatruong]

Tasks:

• [x] Implement authentication context
• [x] Make respective UI changes to different user permission level (guest vs authenticated)
  • [x] Nav bar changes
  • [x] auth: user icon, sign out button, access to create post button
  • [x] guest: sign in button, no create post button
  • [x] Profile changes (?) -- unsure need to get more clarification
  • most likely has to do with restricting ability to "edit" profile info
• [x] Revise routing depending on user permission level (guest vs authenticated)
  • [x] Create forbidden access page
  • [x] Create post page -> redirect to forbidden access page if guest
  • [x] User profile page (?) -> redirect to forbidden access page if guest
  • [x] Sign in page -> redirect to home page if authenticated
  • [ ] Integrate the logout api call

not done; will edit it more later