Handle BigQuery storage errors

[dbolduc]

Related to #4832

As @alvarowolfx points out, BigQuery may encode a StorageError in the error details. We need to make sure this gets preserved when converting between gRPC-generated types and our own types.

This can happen in two place.

1. Converting the status:
   

   google-cloud-rust/src/gax-internal/src/grpc/status.rs

   Line 37 in 266973f

   "type.googleapis.com/google.rpc.DebugInfo" => value

2. Converting protos with rpc::Status as a field:
   

   google-cloud-rust/src/bigquery-write/src/status.rs

   Line 29 in 266973f

   .filter_map(gaxi::grpc::status::any_to_prost)

It will be tricky, because the conversion code lives in gaxi, and we typically do not want that code supporting service-specific types.

We will probably want to extend the interface to accept a custom set of names, Ts, that a service can supply.