Enable Fixed DataTable Header
The table header will remain in the viewport as the user scrolls down the page. The style change of this module is a bit tricky because we need to remove the thead from the normal flow, something that breaks the display of the table. Therefore a helper clone of the thead is used to maintain the table formatting.
Notice #1: The .table-fixed-header class is styled by the _tables.scss and is part of this solution.
Notice #2: This method will take into concern the .content-header element which shouldn't overlap the table header.