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/document_signatures/managers.py

@@ -5,10 +5,10 @@ import os
 
 from django.db import models
 
-from common.utils import mkstemp
-from django_gpg.exceptions import DecryptionError
-from django_gpg.models import Key
-from documents.models import DocumentVersion
+from mayan.apps.common.utils import mkstemp
+from mayan.apps.django_gpg.exceptions import DecryptionError
+from mayan.apps.django_gpg.models import Key
+from mayan.apps.documents.models import DocumentVersion
 
 logger = logging.getLogger(__name__)