This adjusts 53d592ad by @tgxworld
- Adds Sidekiq.upause_all! to unpause all sites
- Adds Sidekiq.paused_dbs to list dbs that are currently paused
- Handles some edge cases where unpause thread could extend expiry on
sites that were unpaused from a different process
- Ensures tests always terminates background thread used for pause
keepalive
If sidekiq is paused or Discourse is in readonly continue to queue
heartbeats
If we do not do that then a master process can end up reaping sidekiq
workers and causing various badness
This also impacts restore which can do weird stuff TM in cases like this
