Expand API driven documentation to reference bootstrap containers

**Path to page with content (_do not_ include domain name):**
`/en/os/1.15.x/concepts/api-driven/`

**What content is incorrect?**

[Bootstrap containers documentation include references to using them to bring in large amounts of settings](https://bottlerocket.dev/en/os/1.15.x/concepts/bootstrap-containers/#use-cases).

This information would be useful to connect to the the API driven documentation.

**What should the content say or communicate?**

Include the bootrstrap containers as a section or at least a reference.