* [Explore] Save url parameters when user save slices
* remove print
(cherry picked from commit bd9ecbe)
* add unit test
(cherry picked from commit 0f350ad)
* wrapping all request params into url_params
(cherry picked from commit 17197c1)
* Introduce an onInit method for when a new viz_type is selected
This allows for clearing certain controls where/when needed. For
instance here, when loading deck_scatter, even if there was a time
granularity picked for the previous viz_type, we want to unselect it.
* making it functional
