Renders a textarea in a form.
'name' - name of the html control. The name is attributized before being rendered.
'value' - a value on html control. Humanized name is default.
'id' - id of the html control. Default is nil.
'maxlength' - maximum lentgh of the field
'rows' - number of rows in textarea
'cols' - number of columns in textarea
'class' - a class used for styling. By default, “textarea”.