[DOC] - Add a video section to demo Nebari features to docs

[Adam-D-Lewis]

Preliminary Checks

• This issue is not a question, feature request, RFC, or anything other than a bug report. Please post those things in GitHub Discussions: https://github.com/nebari-dev/nebari/discussions

Summary

Some Quansight Nebari videos exist, it'd be nice to link to those or create separate ones for the Nebari docs to make it quick to see what Nebari can do without needing to deploy Nebari.

Steps to Resolve this Issue

Add videos