[Bug] The pools of the delegate are being inserted duplicated

[Agupane]

Everytime the jobs runs on the same round and the pools are updated (this not happens unless the developer forces to run), the pools are not updated, but pushed new ones instead. The updateDelegatePools function should be modify to check this before inserting new one (maybe the method findOneAndUpdate could help)

Note: doing the check as db-level is not available in mongo. Check this: https://stackoverflow.com/questions/6743849/mongodb-unique-index-on-array-elements-property