Add with-file-modes macro, and use it

Add with-file-modes macro, and use it

* lisp/subr.el (with-file-modes): New macro.

* lisp/printing.el (pr-save-file-modes):
* lisp/eshell/esh-util.el (eshell-with-file-modes): Make obsolete.

* lisp/emacs-lisp/lisp-mode.el (lisp-el-font-lock-keywords-2):
Add with-file-modes.

* lisp/doc-view.el (doc-view-make-safe-dir):
* lisp/epg.el (epg--start):
* lisp/files.el (locate-user-emacs-file, make-temp-file)
(backup-buffer-copy, move-file-to-trash):
* printing.el (pr-despool-print, pr-call-process, pr-text2ps):
* eshell/esh-util.el (eshell-with-private-file-modes)
(eshell-make-private-directory):
* lisp/net/browse-url.el (browse-url-mosaic):
* lisp/obsolete/mailpost.el (post-mail-send-it):
* lisp/obsolete/pgg-pgp.el (pgg-pgp-verify-region):
* lisp/obsolete/pgg-pgp5.el (pgg-pgp5-verify-region):
* lisp/url/url-util.el (url-make-private-file):
Use with-file-modes.

* doc/lispref/files.texi (Changing Files): Mention with-file-modes.

* etc/NEWS: Mention this.