--no-layer: desactive all the layers except the distribution layer
--distribution: allow the change temporarily the distribution
example
Start emacs with spacemacs-base and no layers:
emacs --no-layer --distribution spacemacs-base
Note that any non Emacsy command line parameter and non processed
command line parameter (that is unknown from Spacemacs) will hide the
home buffer. This should be good enough.
Fixes#4057