Switch the ActiveJob backend from DelayedJob to GoodJob. Differences:
* The job worker is run with `bin/good_job start` instead of `bin/delayed_job`.
* Jobs have an 8 hour timeout instead of a 4 hour timeout.
* Jobs don't automatically retry on failure.
* Finishing jobs are preserved and pruned after 7 days.
* Export daily public database dumps to BigQuery and Google Cloud Storage.
* Only data visible to anonymous users is exported. Some tables have
null or missing fields because of this.
* The bans table is excluded because some bans have an expires_at
timestamp set beyond year 9999, which BigQuery doesn't support.
* The favorites table is excluded because it's too slow to dump (it
doesn't have an id index, which is needed by find_each).
* Version tables are excluded because dumping them every day is
inefficient, streaming insertions should be used instead.
Links:
* https://console.cloud.google.com/bigquery?project=danbooru1
* https://console.cloud.google.com/storage/browser/danbooru_public
* https://storage.googleapis.com/danbooru_public/data/posts.json
