Add CSV bulk download

[tdooner]

Hey, what do you guys think about adding a bulk download option to create a CSV of the data.

The use cases are:

1. internal folks who just want to copy-paste a quick list of brigade information like twitter handles or something and know how to use Excel but not curl
2. people in the brigade community being able to access the data without needing command-line skills

I have been working on a spreadsheet that I'd love to migrate into the CfAPI (https://docs.google.com/spreadsheets/d/1zglhAKDUNnvKindAhb6K_DJaLQ_myRYGKvE2DTYolAQ/edit#gid=1596547592) but, right now, I can't in good conscience suggest that folks use the CfAPI since it's much less user-friendly than a simple google spreadsheet.