TODO: fix tests.

Primary reason for this refactor is to lay the ground-work for keyboard
shortcuts.

- Got rid of components/TracePage#context

- components/TracePage#state.viewRange changed to have `.current` and
  `.next` with `.next` being the "unapplied" change from the mouse UX

- Minimap UX now publishes unapplied changes (user dragging on minimap)
  to `viewRange.next` instead of retaining them in the minimap state

- Minimap rendering changed to draw highlights based on `viewRange.next`
  regardless of UX state

- Color generator now also provides colors in RGB
- ListView now has a public API to inspect the state of the
  ListView scrolling
- VirtualizedTraceView now has a public API to inspect the state of
  the trace view
- SpanGraph scrubbers have wider grips
- SpanGraph minimap rendering update so the spans of large traces are
  more visible
- Tween utility class added
- scroll-page util added for animating window scrolling
- ScrollManager added for scrolling to prev / next visible span,
  sensitive to search filtering
- Keyboard shortcuts added for panning left, right, up down; zoom in,
  out; fast pan, zoom; skip to prev / next visible span

TODO
- Fix tests, add tests
- Reorganize a bit to make things a bit smaller and more
  compartmentalized (a few things are getting a little large)
- Refactor viewRange.next to support animating next position for both
  scrubbers

- Fixed a few tests, there are still broken tests
- Fixed issue in minimap when page resized
- Fixed issue in timeline header row mouse zoom when resize the columns

- Use options object for DraggableManager
- Dont rerender CanvasSpanGraph unless trace changes
- Remove rows, spans from ViewRange

- Make trace minimap colors more prounounced