AbstractService: Move the risk calculations methods into a separate helper class

[xplodwild]

In AbstractService.php around line 677 to 733, the risk calculation methods are directly put as methods.

This doesn't make sense as they are used only in a limited set of services, and should be moved into a separate (helper) class as static methods, as they don't require a specific state nor a specific entity.

[ghost]

Create a trait for risks calculation methods