Add search and filters for categories and products

[frops]

Please, add search and filters for categories and products. It's need, when have many products.

[addgod]

@fulopattila122

What if scout search was added to this project? It would be grate for both frontend and backend.

If you don't mind a PR I can do it.

[addgod]

@fulopattila122

I have made a PR for this.