Also allow a new AcceptContentTypes field to allow the client to ask for
a fallback serialization when getting responses from the server. This
allows a new client to ask for protobuf and JSON, falling back to JSON
when necessary.
The changes to request.go allow error responses from non-JSON servers to
be properly decoded.
Automatic merge from submit-queue
All clients under ClientSet share one RateLimiter.
Currently we create a rate limiter for each client in client set. It makes the reasoning about rate limiting behavior much harder. This PR changes this behavior and now all clients in the set share single rate limiter. Ref. #24157
cc @lavalamp @wojtek-t
