refactor: Move Sprocket JS files to Webpack (Part 2)

Code editor modules are moved with minimal changes.

Relates to #3021

Author: arkirchner

app/assets/javascripts/application.js

@@ -21,12 +21,8 @@
 //= require base
 // 2. Programming groups are required by "channels/synchronized_editor_channel.js"
 //= require programming_groups
-// 3. The turtle library is required by "editor/turtle.js"
-//= require turtle
-// 4. Some channels are required by "editor/editor.js.erb"
+// 3. Some channels are required by "editor/editor.js.erb"
 //= require_tree ./channels
-// 5. Require the editor components, as needed by "./editor.js" and "./community_solution.js"
-//= require_tree ./editor
 //
 // All remaining assets are loaded in alphabetical order
 //= require_tree .