Perform a hard refresh upon signout.
Perform a hard refresh upon signout.

Closes #3458.

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