bcfg2-reports: update to use current models

modified_entry_count() and extra_entry_count() is not available anymore so we have to change it. The other changes are made to unify the model usage.

By the way: Is there any reason there is a badcount() and bad_count in the Interaction model? Especially badcount() does not use the bad_count field available but instead calculates the value via total_count - good_count. Additional to that percentbad also does not use the bad_count field but isclean() uses the bad_count property.