Simplify test runner by adding a new option '--mayan-apps' that

automatically tests all Mayan apps that report to have tests.
Change the app flag that indicates when an app has test
from 'test' to the more explicit 'has_test'.

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

mayan/apps/document_states/apps.py

@@ -36,8 +36,8 @@ from .permissions import permission_workflow_transition
 
 class DocumentStatesApp(MayanAppConfig):
     app_url = 'states'
+    has_tests = True
     name = 'document_states'
-    test = True
     verbose_name = _('Document states')
 
     def ready(self):