Refactor: split code into several django apps (we call them modules).

dav_base/apps.py

@@ -0,0 +1,13 @@
+from .config.apps import AppConfig as _AppConfig, DefaultSetting
+
+DEFAULT_SETTINGS = (
+    DefaultSetting('email_sender', None),
+    DefaultSetting('email_base_url', None),
+    DefaultSetting('email_subject_prefix', ''),
+)
+
+
+class AppConfig(_AppConfig):
+    name = 'dav_base'
+    verbose_name = u'DAV Base App'
+    default_settings = DEFAULT_SETTINGS