Expire view caches when application settings change

Closes #5728

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 
 v 8.4.0 (unreleased)
+  - Expire view caches when application settings change (e.g. Gravatar disabled) (Stan Hu)
   - Implement new UI for group page
   - Implement search inside emoji picker
   - Add API support for looking up a user by username (Stan Hu)

app/views/events/_event.html.haml

@@ -3,7 +3,7 @@
     .event-item-timestamp
       #{time_ago_with_tooltip(event.created_at)}
 
-    = cache [event, "v2.1"] do
+    = cache [event, current_application_settings, "v2.1"] do
       = image_tag avatar_icon(event.author_email, 46), class: "avatar s46", alt:''
       - if event.created_project?
         = render "events/event/created_project", event: event

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

@@ -5,7 +5,7 @@
   - note_count = notes.user.count
 
 - ci_commit = project.ci_commit(commit.sha)
-- cache_key = [project.path_with_namespace, commit.id, note_count]
+- cache_key = [project.path_with_namespace, commit.id, current_application_settings, note_count]
 - cache_key.push(ci_commit.status) if ci_commit
 
 = cache(cache_key) do

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

@@ -5,7 +5,7 @@
 - css_class = '' unless local_assigns[:css_class]
 - css_class += " no-description" unless project.description.present?
 %li.project-row{ class: css_class }
-  = cache [project.namespace, project, controller.controller_name, controller.action_name, 'v2.2'] do
+  = cache [project.namespace, project, controller.controller_name, controller.action_name, current_application_settings, 'v2.2'] do
     = link_to project_path(project), class: dom_class(project) do
       - if avatar
         .dash-project-avatar