Cache commits list

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

app/views/projects/commits/_commit.html.haml

-%li.commit.js-toggle-container
+- if @note_counts
+  - note_count = @note_counts.fetch(commit.id, 0)
+- else
+  - notes = commit.notes
+  - note_count = notes.user.count
+
+= cache [project.id, commit.id, note_count] do
+  %li.commit.js-toggle-container
     .commit-row-title
       %strong.str-truncated
         = link_to_gfm commit.title, namespace_project_commit_path(project.namespace, project, commit.id), class: "commit-row-message"
@@ -9,12 +16,6 @@
         = link_to commit.short_id, namespace_project_commit_path(project.namespace, project, commit), class: "commit_short_id"
 
       .notes_count
-      - if @note_counts
-        - note_count = @note_counts.fetch(commit.id, 0)
-      - else
-        - notes = commit.notes
-        - note_count = notes.user.count
-
         - if note_count > 0
           %span.light
             %i.fa.fa-comments