Add edit link to product variant management page

[brunoslalmeida]

Is your feature request related to a problem? Please describe.
At the product variant management page (http://localhost:3000/admin/catalog/products/ID/manage-variants) is possible to add new variants, create variant group, delete, but it's not possible to edit it and it might cause confusion to the user.

Describe the solution you'd like
Add a link at the Product Variant name (just like in the product page) so the user can open a new page and edit it.

[dlhck]

Could be done together with #2903