Closes #72: Allow to translate authentication required dialog message

tracim/development.ini.base

 # radicale.server.ssl = false
 # radicale.server.filesystem.folder = ~/.config/radicale/collections
 # radicale.server.allow_origin = *
+# radicale.server.realm_message = Tracim Calendar - Password Required
 ## url can be extended like http://127.0.0.1:5232/calendar
 ## in this case, you have to create your own proxy behind this url.
 # radicale.client.base_url = http://127.0.0.1:5232

tracim/tracim/config/app_cfg.py

             'radicale.server.allow_origin',
             '*',
         )
+        self.RADICALE_SERVER_REALM_MESSAGE = tg.config.get(
+            'radicale.server.realm_message',
+            'Tracim Calendar - Password Required',
+        )
 
         self.RADICALE_CLIENT_BASE_URL_TEMPLATE = \
             tg.config.get('radicale.client.base_url', None)

tracim/tracim/lib/daemons.py

         tracim_storage = 'tracim.lib.radicale.storage'
         fs_path = cfg.RADICALE_SERVER_FILE_SYSTEM_FOLDER
         allow_origin = cfg.RADICALE_SERVER_ALLOW_ORIGIN
+        realm_message = cfg.RADICALE_SERVER_REALM_MESSAGE
 
         radicale_config.set('auth', 'type', 'custom')
         radicale_config.set('auth', 'custom_handler', tracim_auth)
         radicale_config.set('storage', 'custom_handler', tracim_storage)
         radicale_config.set('storage', 'filesystem_folder', fs_path)
 
+        radicale_config.set('server', 'realm', realm_message)
+
         if allow_origin:
             try:
                 radicale_config.add_section('headers')