text: Title: docs: djoser endpoint link outdated
  Body: The hyperlink referring to djoser endpoints is outdated (actually, we're using an [older version](https://github.com/desec-io/desec-stack/blob/master/api/requirements.txt#L4), but the link is pointing to `latest`). Link is defined in https://github.com/desec-io/desec-stack/blame/master/docs/endpoint-reference.rst#L5
  
  Proposed solution: update link to https://github.com/sunscrapers/djoser/blob/1.1.5/docs/source/getting_started.rst
  
  It appears that outdated docs are not available on readthedocs.com, but only on github.
  
  