convenient way to fetch non-viewset based api

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Existing helpers (get_detail, get_list) expect that url is a basename of a ViewSet (i.e. model-list).
We often use plain apis without suffix at all (i.e. today or visitor).

There should be a simple way to reverse and to fetch these apis.

• url() method should use basename without - if None is passed as suffix
• add fetch(status, method, data) method to simplify retrieving standalone api views content.