Merge branch 'new-issue-projects-sort' into 'master'

Sort projects by last activity for new issue dropdown

When creating new issue from dashboard page I want to see projects
sorted by last activity instead of ID

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !2702

app/views/shared/_new_project_item_select.html.haml

 - if @projects.any?
   .prepend-left-10.project-item-select-holder
-    = project_select_tag :project_path, class: "project-item-select", data: { include_groups: local_assigns[:include_groups] }
+    = project_select_tag :project_path, class: "project-item-select", data: { include_groups: local_assigns[:include_groups], order_by: 'last_activity_at' }
     %a.btn.btn-new.new-project-item-select-button
       = icon('plus')
       = local_assigns[:label]