tos consent: set on account creation
Created by: limitedmage
Always show the ToS message under the sign up form (previously it was only displayed on Sourcegraph Cloud) and set users.tos_accepted
to true for users that create accounts via the signup form. This happens for users who create accounts via site init or using the built-in authentications. Accounts created via OAuth or via admin invitation will not have this field set to true.
Part of #28716 (closed)