New function read-answer (Bug#31782)

New function read-answer (Bug#31782)

* lisp/emacs-lisp/map-ynp.el (read-answer-short): New defcustom.
(read-answer): New function.
* lisp/subr.el (assoc-delete-all): New function.
* etc/NEWS: Announce them.

* lisp/dired.el (dired-delete-file): Use read-answer.
(dired--yes-no-all-quit-help): Remove function.
(dired-delete-help): Remove defconst.

(backported from master, "New function read-answer (bug#30073)" and
"Respect non-saved value of `read-short-answer' (Bug#31782)")