Rotate secrets, document rotation process

Created by: ElizabethStirling

Rotate all secrets that are now consumed by our secret manager, and document the rotation process. This is mainly going to be asking other devs to perform the rotation and add documentation, since we don't own any of these secrets. Note - we may want to consider keeping the list of secrets & their rotation protocol private for some time. My concern is that it would allow attackers to perform more targeted attacks, and would make it easier for them to find secrets that are accidentally leaked.

Note: also document which pods need to be killed when the secrets are updated.

Dependencies #17813 (closed)

Repository: Handbook