Added intermediate for the takes and emits for the subworkflow nodes

[George-Marchment]

These are the functionctionnalities i've added

• Adding intermediate nodes for the takes and emits (where possible) to the subworkflow nodes (called inputs and outputs)
• Added a Hash map to the DataflowVisitor which stores the values of the conditions when they are visited
• Added a globalNodes attribute to DataflowVisitor to store all the nodes added (this needs to be done to add the intermediate nodes before and after the subworkflows).