Add debug configuration option to provide insight into rephrased query

[cjcenizal]

In vectara/stream-query-client#11 we added support for the debug parameter to Stream-Query-Client.

@ofermend asked that we expose this information in React-Chatbot:

is there a way to expose this information in react-chatbot - the original query, the rephrased query, so it'd be easier for all of us to debug this?

When debug is set, the UI can surface a button for "inspecting" a chat turn. When clicked, it can surface the information provided by debug, for example the rephrased query.