Add setting to remove /about stats & public data

@JammyDodger I have the same feature request, but not for GDPR issues, simply so that none of my competitors can see the activity of our community. Which is something we absolutely would like to avoid.
Competitors can easily figure out that we use Discourse, and hence easily bypass any CSS masking or theming we could do simply by going to the https://[my-community-name]

Should I create a new topic (it is the same feature request but a new use case)?