Tabset improvements

[geoffrey-eisenbarth]

With the upcoming refactor of tabs, we should try to support the following:

• [x] start / end + horizontal / vertical tablists, facilitated by <aria-tabset> container element.
• [ ] close / reopen tabs
• [ ] reorder tabs
• [ ] multiple select tabs (idk i what this looks like visually)
• [ ] scrolling / wrapping tablists, or tablist gets truncated and drop-down menu of remaining tabs shows
• [ ] tabs with actions