retrieveList api for labels

wise-webapp/src/main/java/com/wisemapping/dao/LabelManager.java

@@ -1,6 +1,7 @@
 package com.wisemapping.dao;
 
 import com.wisemapping.model.Label;
+import com.wisemapping.model.User;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.List;
@@ -11,4 +12,6 @@ public interface LabelManager {
 
     void saveLabel(@NotNull final Label label);
 
+    @NotNull
+    List<Label> getAllLabels(@NotNull final User user);
 }