Post Organization MVC: Move Admin Area features to Organization
## Purpose As an effort to create feature parity between self-manage and SaaS users, we want to move the Admin Area capabilities to Organizations and make them available for both SaaS and self-managed. The Admin Area is made up of [different sections](https://docs.gitlab.com/ee/user/admin_area/#admin-area-sections), we will need to move functionality sequentially, possibly grouped by navigation sections. There are nearly 500 features/settings to address, an overview is collected [in this sheet](https://docs.google.com/spreadsheets/d/139BM766XqosbkyZOdPbN9NaClGKl-3amSViSVjor8DU/edit?gid=1662247497#gid=1662247497).
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