Circuit breakers

[bsimpson63]

This is largely copied from reddit/reddit-service-graphql/tree/master/graphql_api/lib/circuit_breaker. That code is great and running in production in a few service.

I added docstrings and types where missing and then added the CircuitBreakerClientWrapperFactory interface to hopefully make it a bit easier to integrate with baseplate service.

I'm going to copy/paste this code into thing service and r2 to ensure it works as expected and isn't missing anything. Then we can consider merging this PR into baseplate.

👓 @suzie-su @pnovotnak @spladug @manishapme @jennLam

[bsimpson63]

Note from Manisha:

only request is some docs that show how you set it up in the tests in the docstring somewhere. like add this to your init.py file

breaker_box = breaker_box_from_config(
            app_config={
                "brkr.samples": "4",
                "brkr.trip_failure_ratio": "0.75",
                "brkr.trip_for": "1 minute",
                "brkr.fuzz_ratio": "0.1",
            }
wrapped_client_factory = CircuitBreakerClientWrapperFactory(
            client_factory, self.breaker_box
        )
baseplate.add_to_context("wrapped_client", wrapped_client_factory)

[manishapme]

🏃‍♂️