Asks for new token given some credentials in the Authorization header.
By default, the authentication scheme is Browser ID but other schemes can potentially be used if supported by the login server. '''app_name''' is the name of the application to access, like '''sync'''. '''app_version''' is the specific version number of the api that you want to access. The first /1.0/ in the URL defines the version of the sagrada token.
Example for Browser-Id: