Feature/event conditions

[AnneHommelberg]

Changes the Activity and Simulation classes to use the events provided by simpy for there start and stop conditions. Also adds a reservation system to the container used by HasContainer, replacing the total_requested field with a more robust system.

Changes to the Activity class: The Condition classes have been removed, as well as the start_condition and stop_condition parameters. These parameters have been replaced with a start_event and stop_event. To get an even similar to the "LevelCondition", use the new "container.empty_event" and "container.full_event" properties on a HasContainer object. To get an event similar to the "TimeCondition", the simpy built-in Timeout event can be used (can be obtained through "env.timeout(...)"). Several events can be combined through the simpy built-in AllOf or AnyOf events (can be obtained through "env.any_of(events=[event1, event2, ...])" or "env.all_of(events=[event1, event2, ...])").

todo:

• [x] add a unit test of a relay case: one activity bringing from container1 to container2 and another activity transporting from container2 to container3.
• [x] refactor the Simulation and Activity classes to use as much of the same methods for their process as possible
• [x] update the example notebooks to the new Activity interface.
• [x] fix the test_infinite_loop test in test_server

[AnneHommelberg]

todo @uijl :

• [x] move the test_dual_processor and test_dual_processors_with_limit tests from test_digital_twin to a new test_requests

[AnneHommelberg]

todo for me:

• [ ] add / update documentation