[DMN Designer] Boxed expressions - Decision Table - Output clause - Selecting a structured type, sub-columns are auto-created

This jira is an enhancement of feature we introduced as DROOLS-3685

Whenever user selects a structured type, the output clauses columns get created with all fields belonging to the chosen structured type.

We can't make the user lose data

if the user already has a column with any data typed in, we have to keep it.

Acceptance criteria

• Action should be undoable/redoable, especially if user had structure data type, more columns with a lot of data and mistakenly change to simple type, i.e. single column
• The feature works just for 1 level of nesting imagine structure below, just single column address will be created

  Person {
    Address { 
      State {
         Code:String,
         FullName:String
      }
    }
  }