Enable User/Project/Group rate limits for self-managed by default

As part of &14995, we want to set these rate limits by default for self-managed in our next major release. The reason for this is that we want instances to be secure and stable by default out of the box, with the best operational learnings from .com baked in. This also reduces the configuration drift between our SaaS services and standard self-managed deployment.

Currently this is planned for 18.0.