feat: Allow bulk library reference migration with auto-publish (#38865)

This adds a new management command:
`migrate_course_legacy_library_blocks_to_item_bank`.
The command migrates legacy library reference blocks in bulk and allows
already-published blocks to be published using the --persist-publish-state
flag, an option which is not currently available in the UI.

Command usage:

  ./manage.py cms migrate_course_legacy_library_blocks_to_item_bank \
    --course-ids course-v1:edX+DemoX+2024,course-v1:edX+Demo2+2024 \
    --user-id 3 \
    --persist-publish-state