* feat(tile-view): initial implementation for mobile
- Create a tile view component for displaying thumbnails in a
two-dimensional grid.
- Update the existing TileViewButton so it shows a label in the
overflow menu.
- Modify conference so it can display TileView while hiding
Filmstrip.
- Modify Thumbnail so its width/height can be set and to prevent
pinning while in tile view mode.
* use style array for thumbnail styles
* change ternary to math.min for expressiveness
* use dimensiondetector
* pass explicit disableTint prop
* use makeAspectRatioAware instead of aspectRatio prop
* update docs
* fix docs again (fix laziest copy/paste job I've ever done)
* large-video: rename onPress prop to onClick
* change forEach to for...of
* use truthy check fallthrough logic instead of explicit if
* put tile view button second to last in menu
* move spacer to a constant
* the magical incantation to make flow shut up
Contributing all buttons in one place goes against the designs that we
set out at the beginning of the project's rewrite and that multiple of
us have been following since then.