* Linter fix

* Addressing code review nitpick, fix CI/CD pipeline

* Fixing ensure_multiple_reviewers.py - mr.discussions.list() needs an extra param to retrieve all of the comments

* Making the linter happy...

* Making the linter happy

* Addressing review comments

* Moved AIRFLOW_INSTANCE_MAP into wmf_airflow_common.config
* Added tests for produced_by sensors
* produced_by sensor task_id abbreviated
* Depending on which Airflow instance is configured in produced_by,
return either ExternalTaskSensor or RestExternalTaskSensor
* Better class and method docs

* Typing and linting fixes

* Adding support for "produced_by" configuration of datasets

Implementation of the proposal outlined in
https://phabricator.wikimedia.org/T372647

Airflow producer dataset annotation

NOTE: Missing implementation of automatic configuration of
`execution_delta` based on target DAG's schedule

Example:

```
  produced_by:
    airflow:
      instance: search
     ...