refactor(role): add CtRole ARGUMENT_TYPE and TYPE_ARGUMENT

[pvojtechovsky]

This PR introduces new CtRole.PARAMETER_TYPE and CtRole.TYPE_PARAMETER_TYPE_TYPE

CtRole.PARAMETER has values of type CtParameter and CtCatchVariable
CtRole.PARAMETER_TYPE has values of type CtTypeReference

CtRole.TYPE_PARAMETER has values of type CtTypeParameter
CtRole.TYPE_PARAMETER_TYPE_TYPE has values of type CtTypeReference

[monperrus]

Why is the change of PARAMETER to PARAMETER_TYPE necessary? Is there a confusion with another role PARAMETER?

The proposed TYPE_PARAMETER_TYPE is good. I propose to rename it to TYPE_ARGUMENT (following the convention parameter (definition)/argument (usage) used in Spoon)

[pvojtechovsky]

Why is the change of PARAMETER to PARAMETER_TYPE necessary?

In #1582 you already suggested this change by this comment:

CtExecutableReference CtRole.PARAMETER -> ||CtExecutableReference CtRole.REF_PARAMETERS

There are two ways:
W1) to use PARAMETER in both CtExecutableReference and CtExecutable. Like this

CtExecutable CtRole.PARAMETER
	ItemType: java.util.List<spoon.reflect.declaration.CtParameter<?>>
	get: getParameters() : java.util.List<spoon.reflect.declaration.CtParameter<?>>
	set: setParameters(java.util.List)
	add: addParameter(spoon.reflect.declaration.CtParameter)
----------------------------------------------------------
CtExecutableReference CtRole.PARAMETER
	ItemType: java.util.List<spoon.reflect.reference.CtTypeReference<?>>
	get: getParameters() : java.util.List<spoon.reflect.reference.CtTypeReference<?>>
	set: setParameters(java.util.List)

W2) to have different roles there

CtExecutable CtRole.PARAMETER
	ItemType: java.util.List<spoon.reflect.declaration.CtParameter<?>>
	get: getParameters() : java.util.List<spoon.reflect.declaration.CtParameter<?>>
	set: setParameters(java.util.List)
	add: addParameter(spoon.reflect.declaration.CtParameter)
----------------------------------------------------------
CtExecutableReference CtRole.PARAMETER_TYPE
	ItemType: java.util.List<spoon.reflect.reference.CtTypeReference<?>>
	get: getParameters() : java.util.List<spoon.reflect.reference.CtTypeReference<?>>
	set: setParameters(java.util.List)

I can imagine that both ways has same advantage, but W2 seems to be more consistent with other roles.
With W2 we are near to contract: each role has same type or one common superType of the attribute (item) value.
The only case where W1 is better is CtPath, where it is better for clients to learn less roles. This problem can be solved by role synonyms: CtRole.ARGUMENT, CtRole.PARAMETER_TYPE and CtRole.PARAMETER might have synonym "parameter". It will be not ambiguous, because there is always only one of them on on each type of element.

[monperrus]

W2) to have different roles there |CtExecutable CtRole.PARAMETER ItemType: java.util.List<spoon.reflect.declaration.CtParameter<?>> get: getParameters() : java.util.List<spoon.reflect.declaration.CtParameter<?>> set: setParameters(java.util.List) add: addParameter(spoon.reflect.declaration.CtParameter) ---------------------------------------------------------- CtExecutableReference CtRole.PARAMETER_TYPE ItemType: java.util.List<spoon.reflect.reference.CtTypeReference<?>> get: getParameters() : java.util.List<spoon.reflect.reference.CtTypeReference<?>> set: setParameters(java.util.List)|

|I prefer W2. Instead of PARAMETER_TYPE it should be ARGUMENT_TYPE.|

[pvojtechovsky]

I am finished. It is ready for merge.