Grouping rows in the configuration list view

[fsuter]

When there are a lot of configurations, the list in the Data Module is a bit cluttered. It could be nice to group rows (according to the "group" property, using DataTables' RowGroup extension (https://datatables.net/extensions/rowgroup/).

However, since the extension currently does not handle expanding/collapsing, this would only be mildly useful in the current state. It's worth keeping an eye on it.