refactor - separate data and http for measurements.
Merge pull request #99 from MastodonC/feature/separate-data-and-http-for-measurements

refactor - separate data and http for measurements.
refactor templates data handling and http apart.
Introduce a download path into the pipeline.

This will generate a csv for download in the background. users will poll
a status URL to see if it's ready.
wip.
wip.