Update list template to stop time error

Hi Jose,

I found that when showing datetime inputs in the list template it displays the 'Object of class DateTime could not be converted to string' error.

As there are a few datetime inputs in my project I thought I would resolve this at the source.

The additions to the code check to see if the datetime attribute exists and if so adds the Common Time class and also will add the format function to the twig datetimes

Hope this helps

Paul