add user ID to airflow as part of payload in execution_context
- As discussed in the above issues we need to remove the 'x-user-id' header from core as we might want to use the service without a service mesh or similar infrastructure.
- As the existing azure code relies on 'x-user-id' header this MR includes the change removing the 'x-user-id' from core part and move to azure provider level.
Original issue: home#52 (closed)