[#1545] Increase resolution of persisted chat messages
[#1545] Increase resolution of persisted chat messages

Messages are stored with seconds which cause messages received within
the same second to have non-deterministic ordering. This increased
resolution will allow these messages to maintain proper order.

OpenBazaar/openbazaar-go,OpenBazaar/openbazaar-go,OpenBazaar/openbazaar-go