Valid default values for search pages

[ReneRanzinger]

Many of the default values provided on the search pages result into "No result found" errors. We should update them.

[senaarpinar]

user examples were not valid, I have changed it to use cfgdata (that comes with the system), still need to change the group/department of cfgdata user and modify the example.
@ReneRanzinger I also changed the dataset examples to use "Demo Experiment" but not sure how to make sure the examples are always valid for this case. We can pick one of the cfg experiments but there won't be a pmid example that would work for cfg experiments.