Rearrange Code Review page order to form a workflow
Add navigation item to global navigation
Adapts the proposal (https://gitlab.com/gitlab-org/gitlab/-/issues/457788) for reorganizing the groupcode review portion of the left nav to account for some pages not listed in the spec.
No edits are made to the links themselves, or their text. Purely a reordering.
Closes https://gitlab.com/gitlab-org/gitlab/-/issues/457788+