Add basic sidebar for adding questions on a dashboard (#16242)

* add useDebounceValue hook

* add AddCardSidebar components

* extract DashboardSidebars component

* use AddCardSidebar component

* remove the old modal for adding questions

* fix specs, unify dashboard toolbar buttons

* fix enterprise specs

* lint

* fix more specs

* maz empty state tweaks

* review

* specs

* add role attributes

* `Add question` => `Add questions`

* add missing onkeydown handler to the QuestionPickerItem

Co-authored-by: Maz Ameli <maz@metabase.com>