QueryExecuter: use configured limit.

This limit usually comes from the parameter MAX_SEARCH_RESULTS. Until we
have all searches using the lazy feature, we still limit the results to
avoid fetching to much (unecessary) data.

For example, when the database has *a lot* of products (more than 50K, for
instance), the product search (one of the most commons) can take a long time
to load (more than 1 minute)

Change-Id: I8435b9ce9179220cc34e74c37c2021ae5371143c