added boolean param to the mqtt node to allow adding a suffix for client id param

rule-engine/rule-engine-components/src/main/java/org/thingsboard/rule/engine/mqtt/TbMqttNode.java

@@ -104,7 +104,8 @@ public class TbMqttNode implements TbNode {
     protected MqttClient initClient(TbContext ctx) throws Exception {
         MqttClientConfig config = new MqttClientConfig(getSslContext());
         if (!StringUtils.isEmpty(this.mqttNodeConfiguration.getClientId())) {
-            config.setClientId(this.mqttNodeConfiguration.getClientId());
+            config.setClientId(this.mqttNodeConfiguration.isAppendClientIdSuffix() ?
+                    this.mqttNodeConfiguration.getClientId() + "_" + ctx.getServiceId() : this.mqttNodeConfiguration.getClientId());
         }
         config.setCleanSession(this.mqttNodeConfiguration.isCleanSession());
 

rule-engine/rule-engine-components/src/main/java/org/thingsboard/rule/engine/mqtt/TbMqttNodeConfiguration.java

@@ -28,6 +28,7 @@ public class TbMqttNodeConfiguration implements NodeConfiguration<TbMqttNodeConf
     private int port;
     private int connectTimeoutSec;
     private String clientId;
+    private boolean appendClientIdSuffix;
 
     private boolean cleanSession;
     private boolean ssl;