Activation key tests

- Removed sleep statements, as wait_for_ajax is working fine.
- updated `update` fn to support environment updation, when we update env, we need to select the CV in that env.
- added a fn `associate_product` to associate custom product to selected activation key
- 7 Tests added  
`test_positive_create_activation_key_3`
`test_positive_create_activation_key_4`
`test_positive_delete_activation_key_3`
`test_positive_delete_activation_key_4`
`test_positive_update_activation_key_3`
`test_positive_update_activation_key_4`
`test_associate_product_2`