[Demo site] Fix /docs generated documentation

[cjcolvar]

Description

The documentation link in the README is to the no-longer running netlify demo site. timeliner.dlib.indiana.edu is a demo site that we maintain but /docs fails to render anything. In the browser console I'm seeing a react error: https://react.dev/errors/130. This error is also present when trying to view the docs locally.

Done Looks Like

• /docs documentation renders and is navigable
• README updated to point to demo site and demo site documentation

[elynema]

/docs is part of the code itself; dynamically built. Should probably wait until we hear about updating the build process.