Last month data should be accurate using last 30 days, not since current date of last month

[lulunac27a]

The view count for last month should be last 30 days, not since current date last month because the days in a month varies from 28 (February) to 31 (January, March, May, July, August, October, and December).

[cristaloleg]

Looks like it should be -1 month AND reset day number to 1. Assuming by "last 30 days" we want data for the last month.

[YaroslavPodorvanov]

I w'll not merge this PR, but i will increase date range in future