Adding a function to properly handle gobble date ranges

[devinmatte]

Motivation

For data where we have monthly data, we don't need every date, but for gobble, we do. So we need a function that handles that for getting data from s3

Changes

• Replaces month_range with s3_date_range
• Adds a MAX_MONTH_DATA_DATE which is the date we have monthly data for

Testing Instructions

Test fetching data for many months in aggregate Test fetching data from Jan 1 - present for buses via url params