Moved color interpolation to separate class, renamed helper to servic… (#2248)

* Moved color interpolation to separate class, renamed helper to service, use snake_case in classes

* Removed abstra

Moved color interpolation to separate class, renamed helper to servic… (#2248)

* Moved color interpolation to separate class, renamed helper to service, use snake_case in classes

* Removed abstract google class

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Testing

Testing

Testing

Testing

Add statistics functions to the test library

Tests

Refactor class User - use NULL-object pattern for guests and temporary users, create UserService

Dependency injection