[doc] reorganize for chapter structure

[web auth] remove assertion, we may want to remove authentication info retreivers to disallow login from the web ui

merge

ask pyro group config questions for all-in-one config site when pyro is enabled in serverctl.py, the pyro questions are not asked for all-in-one configs, because this is webctl.py's responsibility. However for a all-in-one instance, repo_method is "in-memory" so the pyro questions would not be asked even if pyro had been explicitely enabled before.