Add TextAreaStyle

Task-number: QTBUG-33266
Change-Id: I7bcd45469e757f7bde25b62e2324833b85a0ee7f
Reviewed-by: Caroline Chao <caroline.chao@digia.com>
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>