Implement textual export of RequirementConstraintMembership #1786
Description
Implements the textual export of RequirementConstraintMembership such as defined in the BNF
The short handle notation ""ownedRelationship += OwnedReferenceSubsetting FeatureSpecializationPart? RequirementBody"" will only be used for simple case, in all other complex case the form "UsageExtensionKeyword* 'constraint' ConstraintUsageDeclaration CalculationBody" will be used.