Mega menus should now render much faster in CAE (Salesforce and Hybris)

When building links to commerce categories we avoid the loading of the commerce items, at least for Salesforce and Hybris. Unfortunately, it is still necessary for HCL, because links can only be build using technical IDs which must be requested from the commerce system. It should speed up loading of mega menus considerably, at least if a lot of Commerce items are not in the CAE cache.

(CMS-28021)