Improve the docs information architecture and high level information for the Kubernetes integration

Problem to solve

We offer two Kubernetes management solutions but there is no place in the docs that we mention what each of them can be used for, what the benefits and drawbacks of each are, so the visitor is probably left confused or unclear about what the GitLab Kubernetes integration is or does. Also, the two solutions are disconnected in the documentation navigation which creates disparity and doesn't allow the docs reviewer to make a correlation between them and realise that they are both part of the GitLab Kubernetes integration.

Further details

The JTBD for the user that I am trying to solve for is "As a Platform engineer, when I want to manage my Kubernetes infrastructure with my DevOps tool, I want to be able to find the right solution for my organisation's needs.

Proposal

• Create a top level section Kubernetes in the Infrastructure docs.
• Add information about the two Kubernetes integrations we offer.
• Add clear and straightforward information what each solution can be used for, what JTBD each solution serves.
• Add the Agent and cluster integration solutions below.
• Link to related resources (eg. GitOps deployments for the Agent or connecting the CI to the Agent. App installation from the CI for cluster management etc)

Who can address the issue

• Product design (@mvrachni) to propose a hierarchy, sections and content overview
• Technical writing (@marcia) to work with Product management (@nagyv-gitlab) and engineering if required to refine content, ensure information sequence is meaningful and accurate.

Other links/references

• Related design issue: #254998 (closed)
• Doc links:
  • https://docs.gitlab.com/ee/user/clusters/agent/
  • https://docs.gitlab.com/ee/user/project/clusters/add_remove_clusters.html