User flow

[marineks]

Resolves #33 , #23

Features

The user flows goes like this:

1. Login button by default when not connected
2. Correct routes are now linked in Login Page (LogIn,Login w/ 42, SignUp)
3. Error handling: nickname already in use (sign up), password mismatch and nickname not existing in db (log in)
4. When connected, the Login button becomes aAvatar+ log out button immediatly, with a green dot to show they're connected
5. There is also a welcoming message + redirection to homepage. The Chat, that was hidden until so, becomes now visible and expanded by default.

Other

• [x] There is also the addition of a 2FA component (slider button), for now based on the boolean 2FAEnabled. An email address is required.
• [x] .env variables must be preceded by REACT_APP_ to work!!!
• [x] If you need to use it, the isLoggedIn state is managed through React's useContext (in App.tsx)