Add option `dired-filename-display-length'

Add option `dired-filename-display-length'

* lisp/dired.el (dired-filename-display-length): New option.
(dired-insert-set-properties): Set invisible property for long
filenames.
(dired--get-ellipsis-length, dired--get-filename-display-length)
(dired-filename-update-invisibility-spec): New functions.
(dired-mode): Add filename invisibility spec.
(dired-make-directory-clickable)
(dired-kill-when-opening-new-dired-buffer)
(dired-hide-details-preserved-columns): Add missing :group.
* lisp/wdired.el (wdired-change-to-wdired-mode)
(wdired-change-to-dired-mode): Update filename invisibility spec.
* etc/NEWS: Announce the change.  (Bug#67161)