Make graphs' x-axis rolling 30 days instead of starting from 30 Jan

Created by: aman4512

Considering that the number of cases in India was fairly dormant in the first month, showing data from the beginning doesn't make much sense. This is especially true for the linear scale now that number of cases is pretty high.

I believe a 30 day (or some other number) rolling representation of data will be cleaner and easier to see. Can probably add that as an option.