OXUI-488: Contextmenu for Listviews

Feature checklist

• written tests
• written some documentation (if needed)
• added some metrics events (if useful)
• checked on mobile devices (at least in dev tools) will be disabled on mobile
• tested accessibility (semantically correct markup, source-/tab-order)?
• flown over the uxchecklist
• passed usability test (friendly user test)
• may started a SCR to inform about breaking changes (point/ext ids, behaviour, api, distinctive classnames)

Implementation notes

Open issues

• port drive implementation to the more general one also considered out of scope, since this would require a lot of refactoring, which is now tracked as another task in !90 (closed)
• implement for all modules contacts, calendar and tasks still use vgrid, it seems - I consider this out of scope.
• Mail: resolve messages from threads, only using the selection is not enough
• fix “Set color” action removed from context menu alltogether, since it wouldn't work out (dropdown opened from context menu)
• improve UX of “Flag” action
• focus handling
• positioning at (bottom) screen edges for long menus
• unit tests:
  • custom contextmenu ext point reference
  • empty list of resolved menu items