Add suffixes like Ms and Ns to variables whos time unit is not in
seconds. This is aligning with a new code style of putting units
on variables that are not in SI base units.
Use the JSON data class pattern for User, Role, and PlayerStats and move
them into lib/src/data. This means that User is purely data now and
can't reference role objects directly. To make it possible easily check
permissions attached to roles and store data only visible on the
controller on user objects a ControllerUser type is introduced which is
linked with the UserManager and can therefore reference role objects
directly.
Resolves#525.