Summary:
Test suites may now optionally set a "tutorial" flag to
automatically scaffold a sample tutorial document before
the tests run, and tear it down after.
This is used to fix a failing staging deployment test due
to a mismatch between local and staging deployments; local
deployments did not have a sample tutorial document set up,
while staging/prod deployments did.
Test Plan: Existing tests.
Reviewers: jarek
Reviewed By: jarek
Differential Revision: https://phab.getgrist.com/D4354
