Remove Atom feeds and old URLs in the form of GET /:username/updates/:id (#11247)

app/controllers/accounts_controller.rb

@@ -31,13 +31,6 @@ class AccountsController < ApplicationController
         end
       end
 
-      format.atom do
-        mark_cacheable!
-
-        @entries = @account.stream_entries.where(hidden: false).with_includes.paginate_by_max_id(PAGE_SIZE, params[:max_id], params[:since_id])
-        render xml: OStatus::AtomSerializer.render(OStatus::AtomSerializer.new.feed(@account, @entries.reject { |entry| entry.status.nil? }))
-      end
-
       format.rss do
         mark_cacheable!