Add line chart to package comparator #803
Description
As brilliantly suggested by @TheAlexLichter in chat yesterday, including line charts to the package comparator, to compare download trends, is a low hanging fruit, since we already have the plumbing for that.
Optimizations will need to be made on the chart component already used in the enlarged downloads chart.
As for filters, we might impose fixed ranges (would love your input @serhalp), and start with the one-year history default we get through a single call. Edit: the same filters as the modal chart appear to work nicely too from what I can see.
As for the UI side, we can probably iterate, some interactions with the chart could probably be imagined (for example, clicking on x somewhere in the chart can be leveraged to show some detail on the comparator etc)
