Refs: #3934

rescue_old_file: mines info from old config file to use them in new file
translates:
  remote "smth" --> 'remote': {'smth': ...
  global.{url, token} --> remote.default.{url, token}
  <command>.cli --> global.command_cli
  some commands are maped to other names, e.g. pithos --> file
  <command>.url --> remote.defailt.<command>_url