Implement React Router

[DylanTom]

Issue
Currently there is no routing system in place

Task
Use react-router-dom to implement different paths in App.tsx

To-do

• Checkout a new branch
• Create a homepage component, Home in components and migrate everything currently in App.tsx to Home.tsx.
• Use online documentation to create a framework for routing in react in App.tsx
• Create one path "/" whose element is Home
• Create one path "/reservation" whose element is Reservation (use same code for now)
• Create one path "/room" whose element is Room (use same code for now)
• Create one path "/admin" whose element is Admin (use same code for now)
• Create a pull request when done