documentation - Document Iframe Usage

This depends on #1, and #3 being done but this documentation will need to live in its own docs folder in the top level of the project.

TODO: spin up framework for documentation

IF YOU PLAN TO CONTRIBUTE OR WORK ON THIS ISSUE, LETS CHAT FIRST TO SYNC UP.

Review issues #1 and #3 first, since this work depends on them. Then determine the documentation framework and create the docs structure in a top-level docs folder. Done means the framework exists and the iframe usage documentation has a defined place and scope; sync with maintainers before contributing.

Written by the indexing model from the issue text.