Add default constructor to Employee
Add a default constructor to 'User'
Add a default constructor to 'TemorayUser'
Add a default constructor to 'Administrator'
Remove @Table annotation from the subclasses of 'User'

A table name isn't allowed for subclasses
Clean up 'Administrator' and 'Employee'

There were logic functions inside the dataclasses. This shouldn't be the
case!
Remove the logic to get a Page from a User, now it only checks the rights