Revert "Remove setup.py to fix Heroku deploy."
Revert "Remove setup.py to fix Heroku deploy."

This reverts commit 88bf02b586abe5b0db05c08123d183222769b317.

It also should fix documentation building.

mozilla/telemetry-analysis-service,mozilla/telemetry-analysis-service,mozilla/telemetry-analysis-service,mozilla/telemetry-analysis-service