When TTN Bridge was down, HTTP Integrations do not get the missing data

[Danny-Engelman]

eg. When selecting a 6H interval, and the bridge (TTN side) was down for the first 4 hours, then the graph will only display the last 2

TTN can restore the data on their side; so an MQTT connection (requires a per device registration) can get all data.

https://www.thethingsnetwork.org/forum/t/http-integration-will-not-get-data-for-time-period-when-ttn-bridge-is-down/13533

ITpings could detect the missing data gap. Checking how long ago the previous ping was received, and write to the Event log