Sort WorkflowAction classes from the get_all() method.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/document_states/classes.py

@@ -50,7 +50,11 @@ class WorkflowAction(six.with_metaclass(WorkflowActionMetaclass, WorkflowActionB
 
     @classmethod
     def get_all(cls):
-        return cls._registry
+        return sorted(cls._registry.values(), key=lambda x: x.label)
+
+    @classmethod
+    def id(cls):
+        return '{}.{}'.format(cls.__module__, cls.__name__)
 
     @staticmethod
     def initialize():