EZP-23587: As an editor I want to be able to fill DateAndTime field

## Description 

Goal is to be able to fill the dateAndTime field in the edit part. This is working with date HTML5 input, and time HTML5 input, so this is not working with every browser.
Furthermore, currently there is an issue with date and time values, related to timezone. So the values displayed are wrong ever if the process is good.

## Screenshot
Case with some errors and date calendar open : 

![image](https://cloud.githubusercontent.com/assets/5558766/5283419/d4394a84-7b0d-11e4-861e-7e929562254d.png)

## Link
jira : https://jira.ez.no/browse/EZP-23587
I would create a validate method for the required case (`_validateRequired`) and for the non required case (`_validateNotRequired`).