Consider switching from Heroku Scheduler

[nmorduch]

Docs re Scheduler: https://devcenter.heroku.com/articles/scheduler

Considerations include: do we really want to add a whole $25 dyno in order to schedule things manually, which is what heroku seems to recommend doing? See https://devcenter.heroku.com/articles/scheduled-jobs-custom-clock-processes

publish_scheduled_pages

Docs: https://docs.wagtail.io/en/stable/reference/management_commands.html#publish-scheduled-pages

We currently have Heroku scheduler running this every 10 minutes.

Publishing times can be chosen to be on a specific hour, but not a specific minute, so this does not need to be checked more frequently, but if we were handling it we could have it be actually on the hour (which would be people's expected behavior).

update_index

Docs: https://docs.wagtail.io/en/stable/reference/management_commands.html#update-index

I'm trying out (on na-develop) running this every night, but that's not the ideal timing. The docs say:

It is recommended to run this command once a week and at the following times:

• whenever any pages have been created through a script (after an import, for example)
• whenever any changes have been made to models or search configuration

So I think we would ideally run it one night a week, plus mayyyyybe as part of deployment, or as part of deployment when changes have been made, or the night following a deployment? It's hard to tell when is best since it can disrupt the ability to use search. Or we could keep doing it manually after relevant deployment, but it's preferable not to have to sit and watch for when the deployment succeeds.

It would also be worth testing that it search is indeed not usable while it's running.