micromobility OD map: quick usability fixes

[atdservicebot]

https://micro.mobility.austin.gov/

• [ ] shorten default date range to 1 month of data

Repo here: https://github.com/cityofaustin/atd-dockless-dataviz

The goal of this is to improve the performance and initial of the load time from Socrata dataset.

[atdservicebot]

From amenity on 2019-11-18:

Can handle scaling through API; PR open through this.

[amenity]

@mateoclarke - bump to 42?

[amenity]

Prioritizing Moped work and moving this one to the backlog.