TES Callback endpoint and mechanism in TESK

The goal of this project is to implement a callback mechanism for task status updates in TES, which will send requests from the server to the client whenever a task’s status changes, thus eliminating the need for expensive polling. I plan to remove the need of excessve polling by implementing a callback listener microservice which will be deployed as a sidecar with the client. Now, the client can ask this listener instead of making network calls to the server continuouslly.