[TYPO3-mvc] Repository: sort by sorting of relation from mm table

[Moritz Ahl]

I could of course iterate through all demanded categories for and for each category i can call $categoriy->getProducts() and write the result in an array of something. Then, the products for each category are in fact already sorted correctly, and in fact that's what I'm doing right now as a workaround. 

But AFAIK this approach internally produces one DB call for each category, which does not seem well-performing design to me - correct me when i'm wrong.