FIX: deprecation warning - initialization autoloaded the constant (#12400)

Get rid of deprecation related to Zeitwerk autoloader.

Original PR was reverted because of multisite bug #12381 - thank you @davidtaylorhq for fixing it.

I added the last commit to fix that multisite problem.

config/application.rb

@@ -55,6 +55,8 @@ require 'pry-rails' if Rails.env.development?
 
 require 'discourse_fonts'
 
+require_relative '../lib/zeitwerk_config.rb'
+
 if defined?(Bundler)
   bundler_groups = [:default]
 
@@ -116,6 +118,7 @@ module Discourse
     config.autoload_paths += Dir["#{config.root}/lib/validators/"]
 
     Rails.autoloaders.main.ignore(Dir["#{config.root}/app/models/reports"])
+    Rails.autoloaders.main.ignore(Dir["#{config.root}/lib/freedom_patches"])
 
     # Only load the plugins named here, in the order given (default is alphabetical).
     # :all can be used as a placeholder for all plugins not explicitly named.

config/initializers/002-freedom_patches.rb

@@ -1,5 +1,13 @@
 # frozen_string_literal: true
 
+# Multisite freedom patch defines RailsMultisite::DiscoursePatches.config which is used  by 200-first_middlewares.rb
+# Therefore it can not be postponed with .to_prepare
+RUN_WITHOUT_PREPARE = ["#{Rails.root}/lib/freedom_patches/rails_multisite.rb"]
+RUN_WITHOUT_PREPARE.each { |path| require(path) }
+
+Rails.application.reloader.to_prepare do
   Dir["#{Rails.root}/lib/freedom_patches/*.rb"].each do |f|
+    next if RUN_WITHOUT_PREPARE.any? { |path| path == f }
     require(f)
   end
+end

config/initializers/005-site_settings.rb

@@ -16,6 +16,7 @@ if GlobalSetting.skip_redis?
   return
 end
 
+Rails.application.reloader.to_prepare do
   reload_settings = lambda {
     RailsMultisite::ConnectionManagement.safe_each_connection do
       begin
@@ -37,3 +38,4 @@ if !Rails.configuration.cache_classes
       reload_settings.call
     end
   end
+end

config/initializers/100-i18n.rb

@@ -5,6 +5,7 @@
 require 'i18n/backend/discourse_i18n'
 require 'i18n/backend/fallback_locale_list'
 
+Rails.application.reloader.to_prepare do
   I18n.backend = I18n::Backend::DiscourseI18n.new
   I18n.fallbacks = I18n::Backend::FallbackLocaleList.new
   I18n.config.missing_interpolation_argument_handler = proc { throw(:exception) }
@@ -17,3 +18,4 @@ unless Rails.env.test?
       ExtraLocalesController.clear_cache!
     end
   end
+end

config/initializers/100-logster.rb

@@ -1,12 +1,15 @@
 # frozen_string_literal: true
 
 if GlobalSetting.skip_redis?
+  Rails.application.reloader.to_prepare do
     if Rails.logger.respond_to? :chained
       Rails.logger = Rails.logger.chained.first
     end
+  end
   return
 end
 
+Rails.application.reloader.to_prepare do
   if Rails.env.development? && RUBY_VERSION.match?(/^2\.5\.[23]/)
     STDERR.puts "WARNING: Discourse development environment runs slower on Ruby 2.5.3 or below"
     STDERR.puts "We recommend you upgrade to Ruby 2.6.1 for the optimal development performance"
@@ -146,3 +149,4 @@ Discourse.plugins.each do |plugin|
       url: plugin.metadata.url
     }
   end
+end