View rate -- a rankable value that represents the general level of viewer interest in an article (or other page)
Use cases:
* I'm a WikiProject maintainer and I want to sort my worklists by the articles view rate, I cannot really do this well through pageview API as i need to request pageviews for an article since the beginning but I have no "populrity baseline" to compare those to.
* I'm SuggestBot and I'd like to give my users a notion of how often an article is viewed when I recommend that they edit it.
* I'm a researcher and I want to compare the rate that of views with the rate of edits.
Spec:
* Each article would have a single rate.
* A rate could be either one value (average views per <time unit>) or two values (start date of data, total number of views)