Add Migrant Issue Shelter Map

[asteinhart]

What does this PR do?

adds a map using mapbox for the migrant issue stories. followed an example here. putting up an early draft to noodle over with others.

pulled data from map embded on New Arrivals Data Dashboard. @vernonli1 took KML file (in folder as shelters.kml) to convert to geopandas frame and I did some additional light cleaning and converted to geojson for mapbox all in shelters.ipynb file. will probably need to move these somewhere else for better organization.

How was the functionality tested and verified?

All steps should be completed in the order presented, and you should not move on to the next step until the previous is completed.

• [x] The title of the html page is the same as the chart.
• [x] The meta_data.json file is filled in correctly (the description is a complete sentence, the title is the same as the visual).
• [x] The chart and its associated pages have been minified using the npm run process-visual command.
• [x] The visual is styled similar to other charts (centered title/subtitle, no legends unless absolutely necessary, etc.)
• [x] This visual was approved by the lead developer.
• [x] The visual was approved by the story's stakeholders.

[michplunkett]

I'll need you to update the branch before I can look at it.

[asteinhart]

Great work! We discussed some issues with MapBox, they still apply here. Is there another package you can do this with? In this PR #50 you have the Jupyter notebook in the data_analysis folder, I'd like you to add this notebook to that folder as well.

Ya going to move this over to leaflet as well!