Identify parts of visualization state which should be stored in the URL.

[cjcenizal]

Changes

We've succeeded in shortening our URLs by adding the ability to hash the states stored in it. Eventually we will remove even these from the URL. Let's identify parts of the visualization state which are appropriate for putting back into the URL by asking:

1. Are any parts of the vis state which are very useful when surfaced as query params in the URL? For example, refreshInterval and timePeriod, which could be useful when programmatically building URLs.
2. Are these parts of the vis state safe to put in the URL, i.e. is there any possibility they will grow so long as to trigger our IE URL length bug?

[timroes]

I would close this issue for now, since it seems kind of stalled, and there is no active consideration anymore going on, if we should remove parts of the visualize URL. Nevertheless when starting to build the new editor, we def want to give more thoughts into what needs to be part of the URL and what not.