* Improve error handling on LinkCrawlWorker
* Ignore TimeoutError and InvalidURIError too
* Record errors to debug log
* Enable dead job queue on LinkCrawlWorker
Since most of acceptable errors were already ignored, only our side issue should go to dead job queue.
* Ignore all http gem errors
must be added to the Sidekiq invokation in your systemd file
The pull queue will handle link crawling, thread resolving, and OStatus
processing. Such tasks are more likely to hang for a longer time (due to
network requests) so it is more sensible to not make the "in-house" tasks
wait for them.