Update docs to include description of tabby workflow

[jsheunis]

The docs currently suggest using meta-conduct as part of an end-to-end workflow to generate and maintain a catalog from datalad datasets. That information, though practical and useful, is outdated. We have since implemented workflows that include custom scripts and tabby records and datalad-tabby code. These should be included in the docs as another method for generation/maintenance of a catalog.