What does this MR do - Provide context for contributors and others

What does this MR do - Provide context for contributors and others

Moving over DK from Drafts
https://gitlab.com/gitlab-org/professional-services-automation/delivery-kits/draft-delivery-kits/draft-helm-chart-kubernetes-upgrades

What does it change? - Provide an overview of the adjustments this MR

Adds a new upgrade readme doc

Steps for Approvals - Outline steps for Approval if any

Resources - Add link to key resources from branch

https://gitlab.com/gitlab-org/professional-services-automation/delivery-kits/draft-delivery-kits/draft-helm-chart-kubernetes-upgrades