Add setting migrations to apps

Add setting migrations for the common, converter, documents,
file metadata, and document signatures app.

Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>

mayan/apps/file_metadata/settings.py

@@ -5,8 +5,12 @@ from django.utils.translation import ugettext_lazy as _
 from mayan.apps.smart_settings.classes import Namespace
 
 from .literals import DEFAULT_EXIF_PATH
+from .setting_migrations import FileMetadataSettingMigration
 
-namespace = Namespace(label=_('File metadata'), name='file_metadata')
+namespace = Namespace(
+    label=_('File metadata'), migration_class=FileMetadataSettingMigration,
+    name='file_metadata', version='0002'
+)
 
 setting_auto_process = namespace.add_setting(
     global_name='FILE_METADATA_AUTO_PROCESS', default=True,