Show project visibility level on project list

Fixes #3779

app/views/shared/projects/_project.html.haml

@@ -39,6 +39,9 @@
         %span
           = icon('star')
           = project.star_count
+      %span.visibility-icon.has_tooltip{data: { container: 'body', placement: 'left' },
+        title: "#{visibility_level_label(project.visibility_level)} - #{project_visibility_level_description(project.visibility_level)}"}
+        = visibility_level_icon(project.visibility_level, fw: false)
     - if show_last_commit_as_description
       .project-description
         = link_to_gfm project.commit.title, namespace_project_commit_path(project.namespace, project, project.commit),