NGINX: Consume our UBI variant of ingress-nginx/controller

Summary

Following NGINX: Implement CI for UBI container generation (#3382 - closed), we should enable (or default to) the UBI based variant of the ingress-nginx/controller container(s).

If we are not immediatley consuming the Helm chart artifact of https://gitlab.com/gitlab-org/cloud-native/charts/gitlab-ingress-nginx, then we need to swap the registry/repository to point of values.yaml in gitlab-org/charts/gitlab to point to the image that exists from #3382 (closed)

Acceptance

1. Deploying gitlab/gitlab results in UBI / FIPS capable ingress-nginx/controller image being used
2. Documentation of this fact is present, in how to configure and if it is default.