Add QUOTED argument to 'eshell-stringify'

Add QUOTED argument to 'eshell-stringify'

This will make it easier to reconstitute numbers that we converted to
strings.

* lisp/eshell/esh-util.el (eshell--numeric-string-p): New function.
(eshell-stringify, eshell-stringify-list): Add QUOTED argument.
(eshell-convert, eshell-list-to-string): Stringify as quoted.

* lisp/eshell/esh-arg.el (eshell--numberlike-p): Remove.
(eshell-concat-1): Pass along QUOTED.

* lisp/eshell/esh-cmd.el (eshell-lisp-command): Use
'eshell--numeric-string-p'.

* lisp/eshell/esh-var.el (eshell-parse-variable):
* lisp/eshell/em-cmpl.el (eshell-complete-parse-arguments): Stringify as
quoted.

(cherry picked from commit 4d69d3778a51427654965cbcc5bb03611034b656)