[Feature Request] Control panel for failure behavior

[nadvolod]

Let's add a Control Panel to the Instruqt UI as a new tab.
The Control Panel will have a UI slider that controls how often our web requests are failing.
The slider goes from 0 to 100.
0 means web requests never fail. 100 means web requests always fail.
We should be able to set the slider to 100 and watch the activity fail over and over in Temporal UI.
If we slide the slider to 0, this will allow the activity to recover from the error and move on.
The default should be 75% failure rate.
Ask me any other questions for clarification.
Focus on simplicity.