Faster autocomplete for users/issues/emojiis

Instead of loading all issues and merge requests we load only open one.
This will reduce time load for autocomplete resources significantly

app/services/projects/autocomplete_service.rb

@@ -0,0 +1,15 @@
+module Projects
+  class AutocompleteService < BaseService
+    def initialize(project)
+      @project = project
+    end
+
+    def issues
+      @project.issues.opened.select([:iid, :title, :description])
+    end
+
+    def merge_requests
+      @project.merge_requests.opened.select([:iid, :title, :description])
+    end
+  end
+end