Use recommended resources for all n3fit examples

Created by: scarlehoff

Right now most of the example runcards in the n3fit folder force you to unnecessarily download many extra resources. They should be using these instead.

In light of https://github.com/NNPDF/nnpdf/pull/675#issuecomment-799333256 this seems a good time for doing it.

One thing preventing me from doing this change is having some integrability dataset in theory 162 (so that all parts of n3fit can be tested).