[O] [Suggest] Add a command org-attach-sync-all

[tumashu]

I alway forgot to run org-attach-sync when I manual update task's attach dir,

suggest add a sync all command like below:

``` 

(defun org-attach-sync-all ()
    (interactive)
    (org-map-entries #'org-attach-sync)
    (org-align-all-tags))

```