Inputs size > Add the size in css, not with the size attribute

The forms fields needs to be more responsive (NXP-14966).
They now have a 100% width behavior by default.

To update the width in Studio, a size value is suggested. It's not ok because:

• the size attribute is not consistent between each inputs, textarea, etc
• the size attribute value is approximative between inputs and browsers
• the size attribute doesn't override the width style value

The size value should be add in styles as width, not with the size attribute.

More about this:
http://stackoverflow.com/questions/6699575/size-attribute-for-an-input-field-not-being-honored