[DMN Designer] Client-side marshalling tests

Integration tests covering kie-wb-common-dmn-webapp-kogito-marshaller

Unit tests need to cover https://issues.jboss.org/browse/KOGITO-369
Unit tests need to cover https://issues.jboss.org/browse/KOGITO-404 (paymentDate.dmn)
Unit tests need to cover https://issues.jboss.org/browse/KOGITO-371 (Decision Service marshalling)
Unit tests need to cover https://issues.jboss.org/browse/DROOLS-4724 (null default expression).
Unit tests need to cover https://issues.jboss.org/browse/KOGITO-674 (Attachment marshalling)
Unit tests need to cover https://issues.redhat.com/browse/KOGITO-616 (formatted XML String). This is not possible with -webapp-runtime
Simple Business Knowledge Model node
Simple Decision node
Simple Decision Service node
Simple Input Data node
Simple Knowledge Source node
Decision node with simple Context
Decision node with Decision Table
Decision node with Function Java
Decision node with Function PMML
Decision node with Function FEEL
Decision node with Invocation
Decision node with Literal Expression
Decision node with Relation
Decision node with complex Context with Decision Table
Decision node with complex Context with Function
Decision node with complex Context with Invocation
Decision node with complex Context with Literal Expression
Decision node with complex Context with Relation
Business Knowledge Model node with simple Context
Business Knowledge Model node with Decision Table
Business Knowledge Model node with Function Java It's not really necessary to cover all Function types.
Business Knowledge Model node with Function PMML It's not really necessary to cover all Function types.
Business Knowledge Model node with Function FEEL It's not really necessary to cover all Function types.
Business Knowledge Model node with Invocation
Business Knowledge Model node with Literal Expression
Business Knowledge Model node with Relation
Decision Service node with Input Data Covered by the test for KOGITO-371
Decision Service node with input Decision Covered by the test for KOGITO-371
Decision Service node with encapsulated Decision Covered by the test for KOGITO-371
Decision Service node with output Decision Covered by the test for KOGITO-371
Connector Association
Connector Information Requirement
Connector Authority Requirement
Connector Knowledge Requirement
Graph with all nodes and all connector types
Graph with colours and fonts set on nodes
Data Type simple
Data Type simple list
Data Type simple constraint enumeration
Data Type simple constraint expression
Data Type simple constraint range
Data Type structure