- Add CodeMirror XML editor widgets for levelbuilder block edit form fields
- Separate level-editor javascript/css dependencies from main 'application' bundle into 'blockly_editor'
remove default comments from blockly_editor.css.scss
Merge pull request #1093 from code-dot-org/levelbuilder_xml_editor

[Finishes #75389124] Add CodeMirror XML editor widgets for levelbuilder block edit form fields