Centralize the Cloud Connect setup documentation

Cloud Connect is currently available for two features: AutoOps and EIS.

In our current documentation design, the Cloud Connect–related setup instructions live under the specific feature + Cloud Connect documentation pages, rather than under the main Cloud Connect page.

Based on several discussions, we concluded that we should move the Cloud Connect setup steps to the Cloud Connect page and redesign the AutoOps + Cloud Connect and EIS + Cloud Connect pages so that they do not explain these setup steps, but instead link to the setup section on the Cloud Connect page.

This is important because, in the long run, more features are planned that can be used with Cloud Connect, and duplicating setup instructions across multiple feature pages would not scale well.

Resources:

[Cloud Connect](https://www.elastic.co/docs/deploy-manage/cloud-connect) page
[EIS + CC](https://www.elastic.co/docs/explore-analyze/elastic-inference/connect-self-managed-cluster-to-eis) page
[AutoOps + CC](https://www.elastic.co/docs/deploy-manage/monitor/autoops/cc-autoops-as-cloud-connected) page