FIX: migrations-tooling CLI didn't work anymore (#29777)

The previous approach of splitting Thor commands into multiple files caused problems when the same method name was used in multiple commands.

This also loads the Rails environment only for commands that need it. That makes the CLI boot faster for most commands or when the help should be shown. That's also why we can't use `Rails.root` in the CLI.

migrations/lib/cli/upload_command.rb

@@ -1,49 +1,40 @@
 # frozen_string_literal: true
 
-module Migrations::CLI::UploadCommand
-  def self.included(thor)
-    thor.class_eval do
-      desc "upload", "Upload media uploads"
-      option :settings,
-             type: :string,
-             desc: "Uploads settings file path",
-             default: "./migrations/config/upload.yml",
-             aliases: "-s",
-             banner: "path"
-      option :fix_missing, type: :boolean, desc: "Fix missing uploads"
-      option :optimize, type: :boolean, desc: "Optimize uploads"
-      def upload
-        puts "Starting uploads..."
+module Migrations::CLI
+  class UploadCommand
+    def initialize(options)
+      @options = options
+    end
 
-        validate_settings_file!
-        settings = load_settings
+    def execute
+      puts "Starting uploads..."
 
-        ::Migrations::Uploader::Uploads.perform!(settings)
+      validate_settings_file!
+      settings = load_settings
 
-        puts ""
-      end
+      ::Migrations::Uploader::Uploads.perform!(settings)
 
-      private
+      puts ""
+    end
 
-      def load_settings
-        settings = ::Migrations::SettingsParser.parse!(options.settings)
-        merge_settings_from_cli_args!(settings)
+    private
 
-        settings
-      end
+    def load_settings
+      settings = ::Migrations::SettingsParser.parse!(@options.settings)
+      merge_settings_from_cli_args!(@options, settings)
 
-      def merge_settings_from_cli_args!(settings)
-        settings[:fix_missing] = options.fix_missing if options.fix_missing.present?
-        settings[:create_optimized_images] = options.optimize if options.optimize.present?
-      end
+      settings
+    end
 
-      def validate_settings_file!
-        path = options.settings
+    def merge_settings_from_cli_args!(settings)
+      settings[:fix_missing] = options.fix_missing if @options.fix_missing.present?
+      settings[:create_optimized_images] = options.optimize if @options.optimize.present?
+    end
 
-        if !File.exist?(path)
-          raise ::Migrations::NoSettingsFound, "Settings file not found: #{path}"
-        end
-      end
+    def validate_settings_file!
+      path = @options.settings
+
+      raise ::Migrations::NoSettingsFound, "Settings file not found: #{path}" if !File.exist?(path)
     end
   end
 end