During various refactoring, differente methods/implementations get duplkicated all over the code - especially inside the Command stack.
Find and remove duplication,. eventually moving code in common/static methods

Specs

• Remove enable/disable methods from org.drools.workbench.screens.scenariosimulation.client.rightpanel.ListGroupItemView and relative implementation (ListGroupItemViewImpl) and usages because the implementation is empty
• Cleanup org.drools.workbench.screens.scenariosimulation.client.popup.ScenarioConfirmationPopupViewTest: setup() and unused field
• Refactor most execution logic of org.drools.workbench.screens.scenariosimulation.client.commands.actualcommands.PrependColumnCommand and org.drools.workbench.screens.scenariosimulation.client.commands.actualcommands.AppendColumnCommand to a method in a new common abstract class