Connection lost alert

[andreabadesso]

Currently, we don't alert when the websocket connection to the fullnode has been lost, we usually only find out the connection has been lost when we get a CPU spike alert or when the daemon gets a 504 from the fullnode

It is normal that the connection gets broken from time to time, so we shouldn't alert as soon as the connection gets lost, but we should alert after some time thresholds, similar to what we have on the network-monitor

We should also create a major alert when the connection is lost for more than X seconds, as it would indicate that the daemon is not syncing transactions