Add title and description properties

[cdefy]

Make title and description properties available for template separately. Keep text property for retro compatibility.

Questions	Answers
Description?	Made title and description property available for template. They are in different form fields in back-office but there is just "text" available for template so title and description can't be split for display. I just added the two properties to element, but maybe a better improvement will be to update template as well (replace text by title + description)
Type?	improvement
BC breaks?	no
Deprecations?	no
Fixed ticket?	no
How to test?	Update template to use Smarty variables {$element.title} and {$element.description}

[PierreRambaud]

Not sure this one needs QA :)
We can merge after another approval!

[Progi1984]

Thanks @PierreRambaud & @cdefy