ci: Merge registry specific Helm values

[Techassi]

Part of stackabletech/issues#716.

This is a spike PR to test out a bunch of things:

• Publish to multiple registries (This seems a little flaky, also new stuff is private by default)
• Merge registry specific Helm values (CI run)
• Propagate the registry and repository to the operator (tested with make run-dev and make helm-install)

[Techassi]

Most (if not all) of these changes will go into operator-templating.