Circuit breaker for failing downstream resources

A common case is that a task queue worker issues a DDoS against a downstream resource (database, website it scrapes, ...). To reduce the impact of such event, a common pattern is to put in place is a circuit breaker.

This issue proposes to add a circuit breaker to cmdstalk. After scouring the Internet of circuit breaker libraries, I suggest using https://failsafe-go.dev/circuit-breaker/ since it has a `RemainingDelay()` method to make it easy to sleep until the circuit breaker becomes half-open again.