Fix bug where jobs had the opposite of the intended priority. Populating saved searches had the
highest priority, while processing uploads had the lowest priority.
Caused by Delayed::Job and GoodJob having opposite interpretations of job priorities. In
Delayed::Job, lower numbers had higher priority, while in GoodJob, higher numbers have higher
priority. This was missed when migrating from Delayed::Job to GoodJob.
Regenerate posts asynchronously using a delayed job.
Regenerating a post can be slow because it involves downloading the
original file, regenerating the thumbnails, and redistributing the new
thumbnails back to the image servers. It's better to run this in the
background, especially if a user is trying to regenerate posts in bulk.
The downside is there's no notification to the user when the regeneration
is complete. You have to check the modactions log to see when it's finished.
