* lisp/emacs-lisp/package.el: Rename custom faces

* lisp/emacs-lisp/package.el: Rename custom faces

All of the recently introduced faces, like `package-name-face', have
been renamed to no end in `-face' to comply with the convention
described in (info "(elisp) Defining Faces").

(package-name, package-description)
(package-status-built-in, package-status-external)
(package-status-available, package-status-new)
(package-status-held, package-status-disabled)
(package-status-installed, package-status-dependency)
(package-status-unsigned, package-status-incompat)
(package-status-avail-obso): New faces.
(package-menu--print-info-simple): Use them.