Allow to add new options to existing products

[coderjib]

Is your feature request related to a problem? Please describe.
When creating a product, someone can add as many options as he wants (e.g. size, color, etc.), but it seems impossible to add new options once the product has already been created.

Describe the solution you'd like
It should be possible to edit a product and add a new option without deleting the product and re-creating it