Target attributes update can be (re-)triggered by management API (#690)

* extend Management API with attribute `requestAttributes`
* introduce new DMF Event Topic `REQUEST_ATTRIBUTES_UPDATE`
* enhance REST documentation by new functionality
* add tests for:
  * Management API
  * Amqp Message Dispatcher Service
  * Repository (Target Management)

Signed-off-by: Jeroen Jan Laverman (INST/ESY3) <jeroen.laverman@bosch-si.com>

hawkbit-rest/hawkbit-mgmt-api/src/main/java/org/eclipse/hawkbit/mgmt/json/model/target/MgmtTarget.java

@@ -46,6 +46,9 @@ public class MgmtTarget extends MgmtNamedEntity {
     @JsonProperty
     private String securityToken;
 
+    @JsonProperty
+    private boolean requestAttributes;
+
     /**
      * @return the controllerId
      */
@@ -167,4 +170,13 @@ public class MgmtTarget extends MgmtNamedEntity {
     public void setSecurityToken(final String securityToken) {
         this.securityToken = securityToken;
     }
+
+    public boolean isRequestAttributes() {
+        return requestAttributes;
+    }
+
+    @JsonIgnore
+    public void setRequestAttributes(final boolean requestAttributes) {
+        this.requestAttributes = requestAttributes;
+    }
 }

hawkbit-rest/hawkbit-mgmt-api/src/main/java/org/eclipse/hawkbit/mgmt/json/model/target/MgmtTargetRequestBody.java

@@ -24,6 +24,9 @@ public class MgmtTargetRequestBody {
     @JsonProperty
     private String securityToken;
 
+    @JsonProperty
+    private Boolean requestAttributes;
+
     public String getSecurityToken() {
         return securityToken;
     }
@@ -88,4 +91,11 @@ public class MgmtTargetRequestBody {
         this.address = address;
     }
 
+    public Boolean isRequestAttributes() {
+        return requestAttributes;
+    }
+
+    public void setRequestAttributes(final Boolean requestAttributes) {
+        this.requestAttributes = requestAttributes;
+    }
 }