refs #5942
- refactor ghost_head to use Promise.props (settle is going away and this is easier)
- add a new call to fetch the frontend client, if it exists
- add meta tags for the client_id and client_secret on all pages
- don't include the meta tags if the client is not enabled, or if the labs flag is not set
issue #5976
- break out the labs check into a utility
- wrap the get helper in a labs check, so it only works if the checkbox is checked
- make the get helper output an error to both the server and browser console if used when not enabled