add support for not checking callabacks before executing

[tsvetkov-ii]

Airflow declarative supports check callback for importable. If i have different environments for airflow workers i can't build my dags. I want the solution which can work with checking importable callbacks and not. So i add optional flag for open interface of airflow-declarative.

And i change declarative trafaret schema of constants to dynamically chema with functions for purpose of simple changing schema node with config that we can apply on schema validation.

[KostyaEsmukov]

If i have different environments for airflow workers i can't build my dags. I want the solution which can work with checking importable callbacks and not.

Each airflow worker (assuming celery executor) has a queue, and a worker might receive tasks for any callable which is expected to run in that queue. But callables from other queues will never be executed by that worker and indeed might be not importable and this is okay.

So would it be possible to automatically limit the callback checking to those tasks set to a specific queue which the current Airflow worker is listening to instead of disabling the check completely?