Aqueduct

- removed `async-timeout` requirement
- added batching mechanism to the `Worker` class
- changed `handle` method of the `BaseTaskHandler` class for tasks batch handling
- tests refactoring

- fixed segfault error
- added shared fields support in the BaseTask
- removed `to_dict` BaseTask method

- fixed segmentation fault problems due to task update

- source task now updating with result
- process() method returns True if work on task completed

- `need_collect_task_timers` Flow property changed to cached_property
- added the ability to disable the collecting metrics

- fixed unnecessary shared memory warnings