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_parsing/views.py

@@ -6,11 +6,11 @@ from django.shortcuts import get_object_or_404
 from django.urls import reverse, reverse_lazy
 from django.utils.translation import ugettext_lazy as _, ungettext
 
-from common.generics import (
+from mayan.apps.common.generics import (
     FormView, MultipleObjectConfirmActionView, SingleObjectDetailView,
     SingleObjectDownloadView, SingleObjectEditView, SingleObjectListView
 )
-from documents.models import Document, DocumentPage, DocumentType
+from mayan.apps.documents.models import Document, DocumentPage, DocumentType
 
 from .forms import (
     DocumentContentForm, DocumentPageContentForm, DocumentTypeSelectForm