Add util/method to retrieve config from client

[alexdlm]

It would be useful to be able to retrieve config that is passed in to a client, particularly baseUrl, clientId &ontologyRid, probably fetchFn & tokenProvider also, so that these initialization settings don't have to be passed around separately where an osdk client already is.

Some of this is stored internally in a MinimalClient behind the additionalContext unique symbol, or used via factories which are stored on that MinimalClient.