Fix Ghost icon is not clickable
Fix Ghost icon is not clickable

closes #3623
- Initialization of the link was done on login page where the ‚burger‘
did not exist.
- initialization in application needs to be done to make it work on
refresh

kevinansfield/Ghost-Admin,JohnONolan/Ghost-Admin,dbalders/Ghost-Admin,kevinansfield/Ghost-Admin,airycanon/Ghost-Admin,TryGhost/Ghost-Admin,acburdine/Ghost-Admin,dbalders/Ghost-Admin,airycanon/Ghost-Admin,acburdine/Ghost-Admin,TryGhost/Ghost-Admin,JohnONolan/Ghost-Admin