[Feature Request] Add fallback Update/Signal/Query listeners

[roxblnfk]

Is your feature request related to a problem? Please describe.

Right now we declare handlers dynamically using only known names.
It would be nice to have the ability to declare a handler for signals, queries, and updates whose names we don't know in advance.

Describe the solution you'd like

Add something like Workflow::registerListener() function to define fallback update/signal/query listeners

Additional context

Java docs