Cleanup dev-cluster/gh-pages branch

[steezeburger]

The gh-pages branch contains a lot of cruft since we've completed #115.

The gh action now creates github releases for the chart artifacts (the TGZs), where as before the TGZs were uploaded to the gh-pages branch.

We can simply remove all the TGZs from the gh-pages branch. We might even be able to remove everything except the index.yaml file. Will need to figure this out once we start the ticket.