Add Postgres `statement_timeout` to web dyno-originated SQL queries. Use [this config](https://github.com/wemake-services/wemake-django-template/blob/master/%7B%7Bcookiecutter.project_name%7D%7D/server/settings/components/common.py#L93), but only inside web dynos ([use an env var](https://devcenter.heroku.com/articles/dynos#local-environment-variables) to figure this out or set [a new custom one at the Procfile](https://stackoverflow.com/a/38822243/145349)).