Reformat code

Add HttpClient to AuthenticationService
Send request to arsnova backend to gain JWT token for guest user

Add api connection for register

Add getter/setter for AuthenticationService
Create new getter for CreatorRooms

Add constructor
Re-add user role
Update AuthenticationGuard and AuthenticationService accordingly

Reformat code

Create user with freshly generated jwt token

Add HttpClient to AuthenticationService
Send request to arsnova backend to gain JWT token for guest user

Don't return observables in getter functions anymore as we're storing the user in a object we can return immediately.

Store and load user data so we don't lose the user's data on reload.

Added UserRole enum to enable a generic route guard based on roles.