- move getProjectsWithLabelCounts to IDF_Views (where the other functions

reside as well) and make it static
- refactor out the code from getProjects that determines which projects
  are visible by a user and use the same code to restrict the count that
  we calculate for all available project tags
- calculating the project stats is now no longer O(5n) but simply O(5)
  when it comes to SQL queries (where n is the number of filtered projects);
  remove the member statistic since it makes no sense in this context

src/IDF/templates/idf/listProjects.html

@@ -48,7 +48,6 @@
 
 <strong>{trans 'Filtered project stats'}</strong>
 <dl class="statistics smaller">
-<dt>{trans 'Members:'}</dt><dd>{$stats.members}</dd>
 <dt>{trans 'Issues:'}</dt><dd>{$stats.issues}</dd>
 <dt>{trans 'Commits:'}</dt><dd>{$stats.commits}</dd>
 <dt>{trans 'Documentations:'}</dt><dd>{$stats.docpages}</dd>