docs(deployment): updates the deployment prep content and download references

[PaulRMellor]

Documentation

updates the deployment preparation content to make it easier to navigate and in in the TOC
and updates references to the download files and download location

• Expands the downloading files section with links back from related content
• Streamlines the deployment preparation content
• Combines content from "order of deployment" and "deployment path"
• Removes some overlaps with Overview content

Checklist

Please go through this checklist and make sure all applicable tasks have been done

• Write tests
• Make sure all tests pass
• Update documentation
• Check RBAC rights for Kubernetes / OpenShift roles
• Try your changes from Pod inside your Kubernetes and OpenShift cluster, not just locally
• Reference relevant issue(s) and close them after merging
• Update CHANGELOG.md
• Supply screenshots for visual changes, such as Grafana dashboards