feat: react to slotchanged and vertical tabs

[thepassle]

• Improved performance by skipping unnecessary renders. Updates are now batched in a microtask and only executed once
• Improved codesize by extracting SelectedMixin (previously RovingTabindexMixin). Code is significantly smaller when using a combination of accordion/tabs/listbox on the same page
• Optimized execution of querySelectors, skip any unnecessary work
• React to slotchanged event. This is useful when content is added or removed to generic elements
• fixed bug by adding preventDefault on home/end
• made sure IDs are unique when using multiple components on the same page
• allow vertical tabs
  • allow vertical tabs on attr change
• changed docs styles
• add component API to documentation