Support grpc-status-details-bin

[trietsch]

Thanks for this useful browser extension to help in developing gRPC web based apps!

Server side, we're using Google's standard for error_details. This means that potential errors are put in the metadata (in fact, in the trailers section) of the response upon errors. Many clients support this, also tools such as Postman.
It's a standardized way to present errors, be it internal or client side errors.

Any way you see that this will fit in the gRPC web devtools?