Integrate cluster api page into other pages

[viktor-f]

Describe the bug

The cluster api page was meant as a temporary page to highlight the differences between kubespray and cluster api. We should aim to move the information from that page into other existing pages. E.g. the section on egress ip can probably be moved to the networking page.

The part about autoscaling will not be covered in this task. It will instead be done in another task.

For a transition period I suggest that the information is copied to other pages but we leave the cluster api page up as well. Then once the adoption of cluster api is higher we can remove the cluster api page. So once this task is done, you should create a new task for removing the cluster api page.

Definition of done

• Information on the cluster api page (except for autoscaling info) is copied into other pages.
• A new issue is created to remove the cluster api page.