GitLab Helm charts documentation
Getting the Helm charts a first class citizen in our docs site.
## Todos
1. [x] Clean up docs in charts repo to prepare for publication in https://docs.gitlab.com/charts
1. [x] Fleshing out the installation instructions so you don’t need to link out for most details. https://gitlab.com/charts/gitlab/merge_requests/588
1. [x] Review all other top level pages to ensure they are suitable for publication. https://gitlab.com/charts/gitlab/merge_requests/588
1. [x] Publish charts docs to /charts => https://gitlab.com/gitlab-com/gitlab-docs/issues/228| https://gitlab.com/gitlab-com/gitlab-docs/merge_requests/364
1. [x] Add section on difference between GitLab installed on Kubernetes and using the Kubernetes integration https://gitlab.com/charts/gitlab/issues/1140
1. [ ] Update/replace old docs https://gitlab.com/gitlab-org/gitlab-ce/issues/58870
1. [x] Update https://docs.gitlab.com/ee/install/
1. [x] Update https://docs.gitlab.com/ee/install/kubernetes/index.html
1. [x] Do a search for Kubernetes/Charts among CE/EE docs and update any other ce/ee docs that need to link back to the new /charts section.
1. [ ] Any other links in relevant EE/Omnibus pages where you should be looking at the Chart page instead/in addition? Where config differs if using Charts? (This can also be post-MVC)
1. [ ] Add update link to https://about.gitlab.com/install page. When to go with Omnibus or Charts. Until now we say we prefer Omnibus.
1. [ ] Cleanup installation methods
1. [x] Add intro detail on the [main install page](https://docs.gitlab.com/ee/install/). What it offers, diff from other install methods, who should use it. Key differences with future admin. What you need to know going in. => https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/23254.
1. [ ] Make list of install methods even clearer -- a table; could be requirements vs install methods.
? We can highlight Omnibus and Charts as the likely way to go, but then clarify requirements that could shift you in a specific direction -- *including* which cloud provider you know you're using. (And further contextualize the cloud provider list. Review where we link for each; does the linked page in turn offer the right mix of install options for that Cloud provider.)
1. [ ] Outline expected high level structure of related install docs in /charts /ee and otherwise per MVC. (I.e. aspirational MVC structure, for clarity, since there are a lot of install docs.) Review it against a short list of scenarios.
## Runner
1. [x] Update Runner chart https://gitlab.com/gitlab-org/gitlab-runner/issues/2964
epic