added airflow 2.0 stable api support

In Airflow 2.0, they added the new REST API called a stable API. Experimental API still works, but support may be dropped in the future, and the Workflow service is currently using experimental API. This MR includes changes to support airflow 2.0 stable API. Airflow 2.X changes in workflow service provide backward compatibility as well. if any CSP does not want to switch airflow >2.0, they do not have to make any changes.

for more details - ADR - ingestion-dags#65 (closed)
Issue Link - data-workflow#1 (closed)

Procedure to switch airflow 2.0 :

- add following properties

key	values
osdu.airflow.version2	true
osdu.airflow.username	<_airflow_username_>
osdu.airflow.password	<_airflow-password_>

• override and disable integration test case triggerWorkflowRun_should_returnBadRequest_when_givenDuplicateRunId() in provider level. see here
• override and enable integration test case triggerWorkflowRun_should_returnConflict_when_givenDuplicateRunId_with_airflow2_stable_API() in provider level
• see here for more info