Apply remote-file-name-access-timeout in desktop.el and recentf.el

Apply remote-file-name-access-timeout in desktop.el and recentf.el

* doc/emacs/files.texi (File Conveniences):
* doc/emacs/misc.texi (Saving Emacs Sessions):
Mention remote-file-name-access-timeout.

* doc/misc/tramp.texi (Frequently Asked Questions): Add note.

* etc/NEWS: Explain use of 'remote-file-name-access-timeout' in
desktop.el and recentf.el.

* lisp/desktop.el (desktop-access-file): New defun.
(desktop-restore-file-buffer): Use it.

* lisp/recentf.el (recentf-access-file): New defun.
(recentf-keep-default-predicate): Use it.

* lisp/net/tramp.el (tramp-handle-access-file): Improve error handling.