move style for #chart to grapher examples

Not needed in examples.css
model_player keyboard events in Interactive Controller

[#46492719]

Move handling of model_player keyboard events from ModelView
to Interactive Controller.
use tabindex to enable keyboard focus on divs

[#46492719]
Calculate keyboard focus outline color

[#46492719]
use outline keyboard focus on slider handles

[#46492719]
more common sass styling for graph

[#46492719]
refactor keyboard handler in graph

[#46492719]
more focus-relalted style changes
support tabindex properties in components

[#46492719]

Including the model controller.