k8s Foundational Support

Closes https://gitlab.com/gitlab-org/quality/performance/issues/145

MR contains several improvements and changes for supporting the manual creation and validation of the 50k-k8s led environment where the stateless components such as gitlab-rails, sidekiq and registry nodes are deployed via Helm and the rest via Omnibus using our builder.

At this time this environment isn't going to enter regular service and was more of a V1. It was built and tested to a satisfactory level where we proved it was indeed a viable environment for customers as required. Future work would be to codify the Helm deployment in ansible so we can use it's variables (saved for now hardcoded as a snippet), figure out how best to automatically deploy the dynamic secrets and then create the Helm paths.

This MR commits the updates required for the builder to support the above work for now and for any future work as required. It also includes several general improvements and updates.