Revert "Revert (firebase part of) "add uuid and send-time in push payloads""
Revert "Revert (firebase part of) "add uuid and send-time in push payloads""

This reverts commit 3325d51fcefa4dd20a2c45c271b1aa2c75934b51.

BelledonneCommunications/flexisip,BelledonneCommunications/flexisip,BelledonneCommunications/flexisip,BelledonneCommunications/flexisip