Delete new courses' script levels and stages with migration
- Targeting issue #76999866
Merge pull request #1223 from code-dot-org/delete_new_courses_script_levels

Delete new courses' script levels and stages with migration
Merge pull request #1224 from code-dot-org/finished

DTD beta script level position fix
Merge pull request #1225 from code-dot-org/delivered

DTP