Change to static files for KB site

[mattgarrish]

The KB is now using jekyll templates to deploy a static version. As a result, you're not going to be able to use the files in the main branch for the offline version in Ace. The published site is now being served from the public branch.

[danielweck]

thank you Matt.
the git submodule currently points to a past revision (i.e. a specific git commit hash on the main branch), so when we refactor the KB integration we'll migrate to a pointer on the public branch instead.