text: Title: Add internal API reference for datalab adapter modules in docs
  Body: <!-- Please be as detailed as possible in your issue. INCLUDE the exact code you are trying to run, if your question is related to code. -->
  
  
  Include (internal) API reference for the `clenalab.datalab.internal.adapter`  modules ([link](https://github.com/cleanlab/cleanlab/tree/master/cleanlab/datalab/internal/adapter)) in the docs.
  
  Just update this section and add the appropriate files.
  
  https://github.com/cleanlab/cleanlab/blob/325bbe2a77633c87b47f2b275128543f6a5cc980/docs/source/cleanlab/datalab/internal/index.rst#L15-L25