Tabs: Fixed handling of tabs in large view

Fixes #5587

Note that there is a markup change but it is non-breaking. there is a new div class="tabpanels" around all the tab panels. It is needed to properly handle fades and other transitions. For backwards compatibility, for now the JS will add it if it is missing and the CSS smooths out the loading for that scenario.

Existing tabs carousel and tabs implementations should add the new element before v4.1 is released (no date scheduled) as the JS and CSS for backwards compatibility may be removed at that time.

/cc @masterbee