Spring Simplify creating RFC 7807 responses from functional endpoints

This is currently possible, but could be better:

RouterFunctions.route()
    .GET("/path", request -> {
        throw new IllegalArgumentException("...");
    })
    .onError(IllegalArgumentException.class, (ex, serverRequest) -> {
        ErrorResponse errorResponse = ErrorResponse.createFor(
                (Exception) ex, HttpStatus.BAD_REQUEST, null, "Invalid input", null, null);
        return ServerResponse.status(errorResponse.getStatusCode())
                .body(errorResponse.getBody());
    })
    .build()

We could add a ServerResponse#from(ErrorResponse) shortcut, and also provide a builder for ErrorResponse.