Add cl-parse-integer based on parse-integer

Add cl-parse-integer based on parse-integer

* doc/misc/cl.texi (Predicates on Numbers): Document cl-digit-char-p.
(Numerical Functions): Document cl-parse-integer.

* lisp/calendar/parse-time.el (parse-time-digits): Remove.
(digit-char-p, parse-integer) Moved to cl-lib.el.
(parse-time-tokenize, parse-time-rules, parse-time-string): Use
cl-parse-integer.

* lisp/emacs-lisp/cl-extra.el (cl-parse-integer): New function.

* lisp/emacs-lisp/cl-lib.el (cl-digit-char-table): New var.
(cl-digit-char-p): New function.

* test/automated/cl-lib.el (cl-digit-char-p, cl-parse-integer): New
tests.

Fixes: debbugs:18557