Code for stubbing a function for a function call should move to workspace

[RoboErikG]

When the user pastes a function call that doesn't have an associated function definition we create an empty one with the right signature. The code that does this is defined in the onChange methods of the function calls, though. It should be moved into a listener that is registered once on the workspace and handles all types of function calls, not on each function call block.

[rachel-fenichel]

@BeksOmega fyi here's an old issue about procedures.