SOW3 release and bug fixes

Anything from these Milestones:

• https://github.com/Language-Mapping/language-map/milestone/10
• https://github.com/Language-Mapping/language-map/milestone/11
• https://github.com/Language-Mapping/language-map/milestone/12
• https://github.com/Language-Mapping/language-map/milestone/13

Initial stable release

A bit arbitrary relative to the project's Milestones and schedule, but it is live and well.

Initial setup and working demo

Things are very much work-in-progress but this pre-release includes a working demo with:

• Deployment to Netlify
• react-map-gl lib for React/Mapbox integration
• Mapbox tile layer
• NYC language points and counties GeoJSON layers
• TypeScript and eslint setup