Backend and frontend integration for beta

[miahuynhh]

• changed frontend routes:
  • "/user-home" to "/home"
  • "/annotation" to "/project"
• updated home page:
  • backend fetches projects for the logged in user
  • when no existing projects: display mock
  • when >=1 existing projects: display the logged in user's actual home page
• individual project URL:
  • clicking on each project from home page routes to the corresponding project page
  • clicking on "create new project" button fetches a new project id from backend then routes to the corresponding project page