Add getByID() & getByHandle() to DataType & DataList

I want to load object more simple.
ex:
```
$dl = DataList::getByHandle($dtHandle);
$dl = DataList::getByID($dtID);
$dt = DataType::getByHandle($dtHandle);
$dt = DataType::getByID($dtID);
$dt = new DataType($dtHandle);
$dt = new DataType($dtID);
```