Refactor DeepShortcutsContainer to PopupContainerWithArrow

- Also added PopupItemView, which takes animation logic from
  DeepShortcutView, and which DeepShortcutView now extends.
- Renamed ShortcutFilter to PopupPopulator, which has support
  for new item types (not yet used). Also moved populating
  logic (e.g. UpdateShortcutChild Runnable) to PopupPopulator.

Bug: 32410600
Change-Id: Ib6e444ac7ca99c80ba438801c26e62d9542e0ad9