Adds #params_only/#params_except options to filter out params used for pagination links

Filtering out unuseful params in pagination links with +params_except+ and +params_only+
    <%= paginate @users, :params_except => [:utm_source] %>
    <%= paginate @users, :params_only => [:search_params] %>
This filters out 'utm_source' from query params/passed only :search_params parameter to page links.