Use Emacs' variable containing "~/.emacs.d".

Turns out that user-emacs-dir already contains the info I needed, don't
cons it up myself.
Move personalizations into ~/.emacs.d/personal.

Create a "personal" directory, if it has an init.el file, that file will
be loaded.  Moved most of my personal stuff into personal/init.el for now.

If there is a personal/preload/init.el, it will be loaded *before*
graphene is loaded.

Store customizations in personal/custom.el, load it if it exists.