Notification endpoint to accept multiple endpoints

[Remi-Tuy]

Acceptance Criteria

we should be able to setup multiple endpoints in the configurations of the node

notifications:
    endpoint: https://hello.world
    endpoint: https://hello2.world

Expected behaviour

Notifications are sent to the multiple webhooks one after another, the number of webhooks should be limited to 10 to avoid queuing of too many requests.

Actual behaviour

The second endpoint is currently ignored and no notifications are sent to it.