Enable updating product CR generated out of the OpenAPI CR

Currently, the OpenAPIcontroller does a strict comparison between the desired product CR generated out of the OpenAPI CR and the existing product CR.If the user adds something to the product CR generated out of the OpenAPI CR, the OpenAPI controller will revert the changes back.

Implementation here: https://github.com/3scale/3scale-operator/blob/master/controllers/capabilities/openapi_product_reconciler.go#L178-L182

The desired behavior is to allow the user to add 3scale configurations on top of the product CR generated out of the OAS doc. Application plans, extra metrics, methods, policies...

The workflow would be:

• The user creates the OpenAPI CR. The controller creates the product CR.
• The user adds application plans, policies, metrics, methods to the Product CR.
• The OpenAPI controller only reconciles what it matters from the OAS. Probably allowing extra metrics, methods. I would not allow extra mapping rules for security reasons.