Update to use Cogent Lab and new version of Cogent Core

[kkoreilly]

WIP

Important: when merging this, we have to be careful to make sure we incorporate some changes from the main branch (such as the new CNAME and index.html files, and the updates to the new lowercase compcogneuro org name), but also not other changes, like old versions of core and replacing tables with images (the new version of Cogent Core supports tables in htmlcore, so we no longer need them as images).