Display active Manual Task Assistant processes in an IFrame

[raar1]

The MTA is intentionally general, spinning up a server to display the step description and obtain input from the user. This means it can be used in any workflows or scripts, and not only the jupyter-lab environment. However, this extension could perhaps listen on the appropriate port for any active manual tasks, and display them in the widget (probably in an IFrame). This would certainly improve the user experience a lot.