- The conversion server is supposed to be configured in a system preference,
  so do this instead of using a normal preference.
- _getConversionServerDict -> _getConversionServerUrl, to make clear that
  cloudooo is now configured by a url, instead of a host/port couple.
- Refactoring: From the moment where setUpERP5Site() sets up things
  automatically, we don't the "same" duplicated code throughout many test to
  redo cloudooo configuration.
- In the promise file, the volatile/persistent memcached url were swapped.