Display "Project slug" on Project Settings page

The page Project Settings > Overview now includes a new “Project Slug” section, which lets users view and copy in one click the slug of their project.

Please note that both the following project slug formats are valid but mutually exclusive by project:

• github/org-name/project-name
• circleci/FMckQH4sfM6PsIPQEG1RLd/4CNEcx&6Yk6wkpwo2ft9Uo