Re-permission, document, or deactivate public buckets

Created by: ElizabethStirling

app.sourcegraph.com, sourcegraph-public, apktmp, and staging-about.sourcegraph.com are publicly accessible, and I want to verify that they should be. I want to either document their use in the handbook, delete them if they're unused, or restrict them to not be public if they're for internal use only. This is RE: #15542 (closed)

https://sourcegraph.slack.com/archives/C0EPTDE9L/p1605285934177000