Handle root permissions on remote files

Handle root permissions on remote files

* lisp/net/tramp.el (tramp-check-cached-permissions): Check also
for remote uid/gid being 0.  (Bug#57238)

* lisp/net/tramp-sh.el (tramp-do-file-attributes-with-ls):
Convert numeric uid/gid strings into real strings.
(tramp-sh-get-signal-strings): Use `zerop'.

* lisp/net/tramp.el (tramp-root-id-string, tramp-root-id-integer):
New defconsts.
(tramp-handle-find-backup-file-name, tramp-handle-lock-file)
(tramp-local-host-p, tramp-handle-make-auto-save-file-name)
* lisp/net/tramp-sh.el (tramp-default-method-alist)
(ramp-default-user-alist, tramp-find-shell):
* lisp/net/tramp-sudoedit.el (tramp-default-user-alist): Use them.