Allow the setting of mode, group and owner on share directory.

Samba requires that the share directory has proper unix permissions before users can modify it. This pull request adds the functionality to set the owner, group and mode within the shares data bag.
```json
{
  "id": "shares",
  "shares": {
    "export": {
      "comment": "Exported Share",
      "path": "/srv/export",
      "guest ok": "no",
      "printable": "no",
      "write list": ["jtimberman"],
      "create mask": "0664",
      "directory mask": "0775",
      "directory_options": {
        "owner": "jtimberman",
        "group": "users",
        "mode": "0775"
      }
    }
  }
}
```

The mode could also just use the directory mask option, too.