Events support #98

Description

This issue is about adding "events" support to Ankaios. The SDK implementation should be done in accordance with the Ankaios implementation, documented by this issue: eclipse-ankaios/ankaios#450

Goals

The Python SDK supports events:

• The user is able to register an event.
• The user is able to listen to a prior registered event.
• The user is able to unregister said event.
• The event is created in an idiomatic way, with a suitable interface.

Final result

Summary

To be filled when the final solution is sketched.