Improve operator install documentation
Summary
During todays EKS installation demo https://drive.google.com/file/d/1hbem5_ItzqT25GxTshMt7er7Oytcriqr/view?usp=sharing (GitLab internal only)
it was pointed out that the installation documentation for the operator was sparse.
- Not linked to in enough places (only linked to from the deployment page currently)
- Has confusing language on the what
...
are in reference to (additional operator settings or your previous chart settings? It was meant to be the previous chart settings)
The page is located here: https://gitlab.com/charts/gitlab/blob/master/doc/installation/operator.md