[Backend] Show fargate worker status on manage tab

### Description

Using the manage tab challenge hosts can start/stop/restart the challenge workers but they don't get any feedback from EvalAI when worker started/stopped/restarted successfully other than notification when action was executed. As fargate worker takes a few minutes to complete start/stop/restart hosts don't know the status of the challenge worker. We want to show status of fargate worker for each challenge in the manage tab. This status will be updated every 30 seconds (poll duration can be discussed), we will need a polling setup to poll the worker status using boto3 APIs.

### Expected deliverables

1. Polling setup to fetch challenge worker status using boto3 APIs
2. APIs on the backend to fetch worker status
3. Frontend changes to show status on the manage tab