Aded Data Helper and Session Helper

These are two objects I find myself using a lot. I feel like the Class Name "Data" might be a bit too generic and would advise an alternate name, nothing came to mind right away.
i would unpack this line and skip the active check completely:

```lang=php
if ($vars) {
    return array_intersect_key($_SESSION, array_flip($vars);
}
return [];
```