Use ASTNodeDataTypeFlattener to treat function arguments

src/language/ASTNodeDataTypeFlattener.cpp

src/language/ASTNodeExpressionBuilder.cpp

src/language/ASTNodeFunctionExpressionBuilder.cpp

src/language/ASTNodeFunctionExpressionBuilder.hpp

src/language/node_processor/FunctionProcessor.hpp

tests/test_ASTNodeCFunctionExpressionBuilder.cpp

tests/test_ASTNodeFunctionEvaluationExpressionBuilder.cpp