MQTT Configuration builder is not setting the Client Id

[samubura]

https://github.com/wldt/mqtt-digital-adapter-java/blob/a3e06bd8255641391f8914bebff53b6c8f564601/src/main/java/it/wldt/adapter/mqtt/digital/MqttDigitalAdapterConfigurationBuilder.java#L51C1-L55C6

The method is accepting a clientId as parameter but it is not setting it on the MQTT adapter, this means that the client is ignored.

Also the generation of the ClientID is done with

"wldt.mqtt.digital.adapter.client."+new Random(System.currentTimeMillis()).nextInt()

Which apparently is creating issues and potential clashes when a lot of DTs on the same process are launched at the same time.

Maybe we should simply make the clientID mandatory.