Port old API tests for products

Make module `test_product_v2` accomplish the same goals as module
`test_product`. Remove the latter module and update the API documentation
accordingly.
Since you're specifically updating attributes (and not say only names or descriptions), and very much like ``test_positive_create_1``, then is there a reason for not including all char types (missing are ``cjk`` and ``latin-1``) for both ``name`` and ``description``?