UX: Make the api-keys new and show page a little more responsive (PR #10629)

/admin/api/keys/new, and /admin/api/keys/:id pages are not very mobile-friendly. These changes attempt to improve that a little.

Creating a new API Key from a phone: Screen Shot 2020-09-08 at 15 33 23

Viewing an API Key from a phone:

Screen Shot 2020-09-08 at 15 32 59

GitHub

Looks nice!