OKRs - Objective drill down view

Show OKRs in a tree view instead of list view. Ideal behaviour would be something similar to what we have at instance level. for example gitlab home page https://gitlab.com/gitlab-org

Initial discussion is capture here - https://docs.google.com/document/d/12cY8ary4c2p8wjmeTgaJFZmlPwElWvkf7Kfe6s6oRCE/edit#bookmark=id.i4dpr5sbs6b0