Traces: Migrate pagination to bootstrap

Same feature, different style.
- Change pagination to use bootstrap default styles
- … but with empty span-tags instead of non-active a-tags
- refactor partial to not use @-variables but get the variables via
the render-call, simplify render-call-syntax
- remove the additional `if @traces.size > 1` inside the pagination
partial since that caused the pagination to disappear on the last page.
The partial will be visible with inactive links.
- Add bootstrap spacer-classes to overwrite commons-css so removing. Eg.
commons also has a pagination class same as bootstrap.

app/views/traces/index.html.erb

@@ -23,15 +23,15 @@
 <% end %>
 
 <% if @traces.size > 0 %>
-  <%= render :partial => "trace_paging_nav" %>
+  <%= render "trace_paging_nav", :page => @page, :page_size => @page_size, :traces => @traces, :params => @params %>
 
-  <table id="trace_list" class="table table-borderless table-striped">
+  <table id="trace_list" class="table table-borderless table-striped mb-0">
     <tbody>
       <%= render @traces unless @traces.nil? %>
     </tbody>
   </table>
 
-  <%= render :partial => "trace_paging_nav" %>
+  <%= render "trace_paging_nav", :page => @page, :page_size => @page_size, :traces => @traces, :params => @params %>
 <% else %>
   <h4><%= t ".empty_html", :upload_link => new_trace_path %></h4>
 <% end %>