Switch to full app paths

Instead of inserting the path of the apps into the Python app,
the apps are now referenced by their full import path.

This solves name clashes with external or native Python libraries.
Example: Mayan statistics app vs. Python new statistics library.

Every app reference is now prepended with 'mayan.apps'.

Existing config.yml files need to be updated manually.

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

mayan/apps/django_gpg/apps.py

@@ -2,13 +2,13 @@ from __future__ import absolute_import, unicode_literals
 
 from django.utils.translation import ugettext_lazy as _
 
-from acls import ModelPermission
-from acls.links import link_acl_list
-from acls.permissions import permission_acl_edit, permission_acl_view
-from common import (
+from mayan.apps.acls import ModelPermission
+from mayan.apps.acls.links import link_acl_list
+from mayan.apps.acls.permissions import permission_acl_edit, permission_acl_view
+from mayan.apps.common import (
     MayanAppConfig, menu_facet, menu_object, menu_setup, menu_sidebar
 )
-from navigation import SourceColumn
+from mayan.apps.navigation import SourceColumn
 
 from .classes import KeyStub
 from .links import (
@@ -24,10 +24,11 @@ from .permissions import (
 
 
 class DjangoGPGApp(MayanAppConfig):
-    app_url = 'gpg'
+    app_namespace = 'django_gpg'
+    app_url = 'keys'
     has_rest_api = True
     has_tests = True
-    name = 'django_gpg'
+    name = 'mayan.apps.django_gpg'
     verbose_name = _('Django GPG')
 
     def ready(self):