WIP - Feature/ajaxify filter list

| Q                   | A
| ------------------- | ---
| Bug fix?            | No
| New feature?        | No
| BC breaks?          | No
| Tests pass?         | ?
| Scenarios pass?     | ?
| Checkstyle issues?  | ?
| Changelog updated?  | No
| Fixed tickets       | No
| Doc PR              |

Ajaxifies the filters list in the product grid
The PR is not complete, and not perfect. The aim is mainly to help the core team develop it nicely, it is only a port of some code I had to do on the client side.