added a SHA1 hash on file uploads to S3 so that we can verify uploads async with the backup process
added task to clean up CellMeasure records if the archive is valid
dropped CellMeasureCheckPoint
changed start_cell_measure_id and end_cell_measure_id to start_id  and
end_id
renamed methods so that i can tease out a wifimeasure version of the
cellmeasure backups
fixed a couple off by 1 errors when computing batches
flake8 fixes
dropped CellMeasureBlock in favor of MeasureBlock to consolidate
tracking of Cell vs Wifi measure archival