Add new app to handle all dependencies

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

mayan/apps/metadata/apps.py

@@ -29,6 +29,7 @@ from mayan.celery import app
 from mayan.apps.navigation.classes import SourceColumn
 
 from .classes import DocumentMetadataHelper
+from .dependencies import *  #NOQA
 from .events import (
     event_document_metadata_added, event_document_metadata_edited,
     event_document_metadata_removed, event_metadata_type_edited,
@@ -152,6 +153,7 @@ class MetadataApp(MayanAppConfig):
             )
         )
 
+
         SourceColumn(
             source=Document, label=_('Metadata'),
             func=lambda context: get_metadata_string(context['object'])