Add new prop to disable css transitions on expandable rows

[dalmau]

Added new boolean prop "cssTransitions" to keep rows always expanded in the scenario where you want that all the table is expanded by default.

The default behaviour makes css transition closing and opening the row if the header is clicked, loosing scroll position of the table if it's embedded on a fixed height container. If the new prop is set to false the component CSSTransition won't be rendered.