Add support for keyboard navigation in Collection.

You can use <left>, <right>, <tab> and <backtab> to jump between the
filter view and the collection view. If the search input field is
focused, you can use <down>, <tab> and <backtab> to jump back to the
collection view.
Add focus behavior on Collection's search input.
Add application's menu “edit“.

The edit menu contains a “search“ item (Ctrl+F) which focuses on the
search field in the Collection component.