Have an HTTP endpoint for ECS to respond with task status

[bewakes]

Currently:

1. NLP server sends http request to ecs container.
2. ECS container sends acknowledgement to NLP server and then triggers the actual task.
3. Upon the task completion/failure, ECS container directly upates NLP server's database with appropriate status for that task.

This is fragile and ECS has to know about database structure. So we need to have http endpoint in nlp server instead of direct db access by ecs.

cc: @ranjan-stha