Adding support for EFS mounts.

Changelog:
* Upgraded CDK version to support EFS usage
* Upgraded Fargate PlatformVersion to support EFS mounts
* Refacored RDS contruct as per new CDK
* Created a new LogGroup for OnDemand DagTasks
* Added TAG for stack, to track resources belonging to this setup
* Updated sample DAG to utilize EFS. Tasks Odd and Even will publish to EFS and Numbers will read from EFS
* Now you can see logs from OnDemand tasks on Airflow UI, once task run finishes

tasks/multi_task/even_numbers.py

@@ -8,6 +8,9 @@ if __name__ == '__main__':
     number = args.number
     
     print("Printing Even numbers in given range")
+    f = open("/shared-volume/even.txt", "a")
     for i in range(int(number)):
         if(i % 2 == 0):
+            f.write(str(i))
             print(i)
+    f.close()

tasks/multi_task/odd_numbers.py

@@ -8,6 +8,9 @@ if __name__ == '__main__':
     number = args.number
 
     print("Printing Odd numbers in given range")
+    f = open("/shared-volume/odd.txt", "a")
     for i in range(int(number)):
         if(i % 2 != 0):
+            f.write(str(i))
             print(i)
+    f.close()