[Feature][api]Export and import workflow add processDefinitionDescription #3808 (#3847)

* add .asf.yaml file

* export processDefinition add desc

* clear conentent in .asf.yaml

* delete .asf.yaml file

Co-authored-by: guirong.ggr <guirong.ggr@dtwave-inc.com>

dolphinscheduler-api/src/main/java/org/apache/dolphinscheduler/api/service/impl/ProcessDefinitionServiceImpl.java

@@ -683,6 +683,7 @@ public class ProcessDefinitionServiceImpl extends BaseService implements
         exportProcessMeta.setProjectName(processDefinition.getProjectName());
         exportProcessMeta.setProcessDefinitionName(processDefinition.getName());
         exportProcessMeta.setProcessDefinitionJson(processDefinition.getProcessDefinitionJson());
+        exportProcessMeta.setProcessDefinitionDescription(processDefinition.getDescription());
         exportProcessMeta.setProcessDefinitionLocations(processDefinition.getLocations());
         exportProcessMeta.setProcessDefinitionConnects(processDefinition.getConnects());