Add variables read-char-choice-use-read-key and y-or-n-p-use-read-key

Add variables read-char-choice-use-read-key and y-or-n-p-use-read-key

* lisp/subr.el (read-char-choice-use-read-key): New variable.
(read-char-choice): Use read-char-from-minibuffer when
read-char-choice-use-read-key is nil.
(y-or-n-p-use-read-key): New variable.
(y-or-n-p): Restore old code that calls read-key to use it when
y-or-n-p-use-read-key is non-nil.

* lisp/dired-aux.el (dired--no-subst-ask, dired-query):
* lisp/files.el (files--ask-user-about-large-file)
(hack-local-variables-confirm):
* lisp/userlock.el (ask-user-about-supersession-threat):
* lisp/wid-edit.el (widget-choose): Revert to use read-char-choice
instead of read-char-from-minibuffer.

https://lists.gnu.org/archive/html/emacs-devel/2020-12/msg01919.html