Define content for SDK host

If you want to connect to the public api server you will use the default settings. Howwever if you want to connect to a private environment (e.g.,, you can use environment variables to define the host:

def create_url(subdomain, environment):
    if environment:
        subdomain = subdomain + '.' + environment

    return 'https://{}'.format(subdomain)

API_HOST = environ.get('DW_API_HOST', create_url('api', DW_ENVIRONMENT))
DOWNLOAD_HOST = environ.get(
    'DW_DOWNLOAD_HOST', create_url('download', DW_ENVIRONMENT))
QUERY_HOST = environ.get('DW_QUERY_HOST', create_url('query', DW_ENVIRONMENT))