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/documents/forms.py

@@ -7,8 +7,8 @@ from django import forms
 from django.template.defaultfilters import filesizeformat
 from django.utils.translation import ugettext_lazy as _
 
-from acls.models import AccessControlList
-from common.forms import DetailForm
+from mayan.apps.acls.models import AccessControlList
+from mayan.apps.common.forms import DetailForm
 
 from .fields import (
     DocumentField, DocumentPageField, DocumentVersionField