Generate transient schema for global variables when used in node form

When designing a node form:

• both global (workflow) variables and local (node) variables will still be available
• a dedicated transient schema will be generated to handle global variables that are editable within a node
• on platform side, when completing a task
  • a transient DocumentModel will be created associated with the node schema handling the local variables + the transient schema handling the global variable used within the form
  • From the variables map (workflow + node) submitted for task completion, the 2 schema fields will be valued
  • if the wokflow variable map contains a variable that does not match one of the field of the transient schema, a security exception is thrown (this means we are trying to edit a global variable within a task completion that we are not allowed to)
  • the validation is processed on this DocumentModel but nothing is persisted.
  • if the validation went through, the workflow engine will complete the task and run as it is

At this point, nothing change in the workflow design UI.