move sql files in the python package qand update tests according to D538
also delete unused file swh-scheduler-testdata.sql and fix sql/Makefile and sql/updater/sql/Makefile to make them properly generate svg/pdf images and make.
Related to swh-storage#1265 (closed).
Test Plan
all tests should pass provided swh-core!16 (closed) is applied in swh-core
Migrated from D541 (view on Phabricator)