Persistent settings on the kepler component

[chrisgervang]

Currently the settings are reset whenever the video export component for kepler is closed. This makes iteration very difficult.

It'd be better if the view state and render settings were saved and recalled whenever the window opens.

[akre54]

This feels like something that should live in a persistent timeline object. Definitely better if it was attached to the Kepler data structure in the first place, that way it could be manipulated by the python sdk, or exported, for instance

[chrisgervang]

Yeah, maybe the same data structure as #263? What do you think?