Add app.rb and helpers.rb back

Those files were removed in rails#51760, but gems like `console1984` depend
on these files for legacy Rails console command extensions.
So keeping files around is required for backward-compatibility.

Author: st0012

railties/lib/rails/console/app.rb

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+ActiveSupport::Deprecation.new.warn(<<~MSG, caller_locations(0..1))
+`rails/console/app.rb` has been deprecated and will be removed in Rails 8.0.
+Please require `rails/console/methods.rb` instead.
+MSG
+
+require "rails/console/methods"

railties/lib/rails/console/helpers.rb

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+ActiveSupport::Deprecation.new.warn(<<~MSG, caller_locations(0..1))
+`rails/console/helpers.rb` has been deprecated and will be removed in Rails 8.0.
+Please require `rails/console/methods.rb` instead.
+MSG
+
+require "rails/console/methods"