Set Transaction UUID for events

[kristinapathak]

With this change to the spec for WRP SimpleEvents, the TransactionUUID will be required.

When creating online and offline events, we should create and add TransactionUUIDs to the WRPs:

talaria/deviceStatus.go

Line 48 in 3db2d63

func newOnlineMessage(source string, d device.Interface) (string, *wrp.Message) {

talaria/deviceStatus.go

Line 88 in 3db2d63

func newOfflineMessage(source string, d device.Interface) (string, *wrp.Message) {

There is currently a bug in Caduceus where Caduceus is setting any empty TransactionUUIDs. As far as I know, this logic should now be moved into Talaria.