Replace generator model typesystem with Generic Type System

[andreasmuelder]

The generator model has a very simple type system implementation with 4 basic primitive types and basic type checks. This should be replaced by org.yakindu.base expressions to reduce duplicate code.

[terfloth]

We have to check if this is topic for a major release as this may break compatibility.

[andreasmuelder]

This would also allow to use expressions and variables in SGen for instance

GeneratorModel for yakindu::java {

 var targetSubFolder : string = "mySubFolder"
 var generateTimerServce : boolean = true

statechart ECU_B {   

    feature Outlet {
        targetProject = "TargetProject"
        targetFolder = "target/" + targetSubFolder
        libraryTargetFolder = "src"
    }  
    
    feature GeneralFeatures {
        TimerService = generateTimerServce
    }
}

}