Table layout: change sort via column headers#438

Clicking a column header sorts all entries by that column (toggling between ASC and DESC)

This is a must have feature for the table layout.

It could be active by default or enabled/disabled on each column using sortable: true, like @Sylvain Julé did on his pagetable plugin.

same here. But if the table included in Kirby could handle: Column sorting + filtering, it would be awesome!