way to export index data

[wileyj]

Related to our discussion and forum post
I'd propose the following:

adding a function that will upload the resultant data to a cloud storage bucket (i.e. s3), through some config settings - either hardcoded file, or preferably with env variables like this:
BUCKET_NAME
CLOUD_PROVIDER
CLOUD_USER
CLOUD_KEY

and then, in blockstack-core, a new endpoint is exposed to use this public readable bucket to retrieve the data.
initially, the vars would need to be hardcoded (which could result in drift), but i have ideas on how to resolve that in the future.