Add active nav state to edit deploy keys

What does this MR do and why?

• Adds active nav state and breadcrumb for the project-level Edit deploy keys page
• Sentence case Repository settings

Screenshots or screen recordings

Before	After

How to set up and validate locally

http://gdk.test:3000/gitlab-org/gitlab-test/-/deploy_keys/13/edit

Links

• ✂️ UX Paper Cuts 18.1 → Mixed milestone (#513102 - closed)