work with API tokens (new since indico 3.0)
Since indico v3.0 the recommended API authentication uses tokens, which are passed as headers to the HTML request - while the old authentication is deprecated. With the changes proposed in this merge request, the API token - if available - is used instead of the API key/secret key pair.
For backwards-compatibility reasons, the ~/.indico-secret-key
is still assumed to be the place where API key/secret key pairs are to be found whenever no keys/tokens are provided.