One of the prospects requested this feature to simplify their process of setting up POC during the trial period.

We already had this feature back in the older versions (prior to 3.8), but then removed https://github.com/sourcegraph/sourcegraph/pull/5514 to avoid abuse usage.

We should return back this ability to make instance publicly available based on auth.public site config, but also with additional specific license tag check (smth like allow-anonymous-usage), that CEs will use only for special occasions.

cc @sourcegraph/iam @ryphil