feat: enable host rules detection from env for Renovate

What

Enable host rules detection from env for Renovate (https://docs.renovatebot.com/self-hosted-configuration/#detecthostrulesfromenv).

Why

So that we can configure credentials for various registries in the CI configuration.

Part of the consolidation effort, as this will allow us to switch to common-ci-tasks in the Helmfile and Terraform projects: production-engineering#16148