Factor out vc-only-files-state-and-model

Factor out vc-only-files-state-and-model

* lisp/dired-aux.el (vc-compatible-state): Delete declaration.
(vc-only-files-state-and-model): Declare.
(dired-vc-deduce-fileset): Factor out vc-only-files-state-and-model.
* lisp/vc/vc-dir.el (require): Require cl-lib at load time, too.
(vc-only-files-state-and-model): Declare.
(vc-dir-deduce-fileset): Factor out vc-only-files-state-and-model.
* lisp/vc/vc.el (vc-only-files-state-and-model): New function,
factored out of dired-vc-deduce-fileset and vc-dir-deduce-fileset.

(cherry picked from commit b784f194f8320d326c755dd49b31210977aae0e7)