Set up build process for Data map web UI

[nikolajbaer]

The ultimate presentation of Tacos' and Transit will be a map where people can explore the different taco stands and visualize their accessibility (as well as perceive overall neighborhood accessibility by public transit.

The broader goal, though, is to perhaps have a re-usable Map tool for Open San Diego to showcase / communicate some of the community data and projects that it has developed.

This task is to setup a basic front-end application setup for this web UI. This is typically a package.json and other pieces (e.g. webpack). Right now it is roughed out in data.html as all embedded and externally referenced scripts.