rpc: add HTTPError type for HTTP error responses (#22677)

The new error type is returned by client operations contains details of
the response error code and response body.

Co-authored-by: Felix Lange <fjl@twurst.com>

rpc/types.go

@@ -35,18 +35,6 @@ type API struct {
 	Public    bool        // indication if the methods must be considered safe for public use
 }
 
-// Error wraps RPC errors, which contain an error code in addition to the message.
-type Error interface {
-	Error() string  // returns the message
-	ErrorCode() int // returns the code
-}
-
-// A DataError contains some data in addition to the error message.
-type DataError interface {
-	Error() string          // returns the message
-	ErrorData() interface{} // returns the error data
-}
-
 // ServerCodec implements reading, parsing and writing RPC messages for the server side of
 // a RPC session. Implementations must be go-routine safe since the codec can be called in
 // multiple go-routines concurrently.