use workqueue to avoid blocking

[ZYecho]

for the etcd-operator, is there a need to use workqueue to avoid blocking? I find a TODO leaves in code, and for the etcd-restore/backup operator, they use workqueue to avoid blocking, if need, I would like to help
to do it. :) also related to issue #1410

[raoofm]

I guess rather redoing it using operator-sdk