add bookinfo example based on dubbogo and pixiu

**What would you like to be added**:

bookinfo example from https://istio.io/latest/zh/docs/examples/bookinfo/

**Why is this needed**:

to demonstrate how to use dubbogo and pixiu

Start by reviewing the Istio Bookinfo example at https://istio.io/latest/zh/docs/examples/bookinfo/ and the existing dubbogo and pixiu samples in this repository. Done means a Bookinfo example is added that demonstrates how to use dubbogo and pixiu, with the example's scope and run instructions made clear.

Written by the indexing model from the issue text.