Show instance status

[soichih]

I need to put instance status maker back to let user know which one is running, finished, failed, etc..

At the moment, there is no instance status that aggregates all tasks running inside the instance which makes this a bit difficult. I believe I need to do following.

1. When a task status changes (not when task gets updated), update instance status[] field.
2. Above implies adding task status[] under instance (again..)
3. Emit event when instance record gets updated
4. Update UI to subscribe and receive the instance update event
5. Update UI to calculate the current instance status based on task status.

[soichih]

Instance now has "status" field that I can display - but we also need to subscribe to instance update event to update the instance status.