made sende2e return the timestamp in the sent message

api/send.go

api/utilsInterfaces_test.go

bindings/message.go

bindings/send.go

cmd/root.go

groupChat/sendRequests.go

groupChat/utils_test.go

interfaces/networkManager.go

keyExchange/rekey.go

keyExchange/trigger.go

keyExchange/utils_test.go

network/ephemeral/testutil.go

network/message/critical.go

network/message/sendE2E.go

network/send.go

single/manager_test.go