Create minimal lp_load management command for Learning Core

[dwong2708]

Summary

This issue introduces the initial implementation for restoring a learning package from a ZIP archive. It lays the groundwork for handling backup and restore of course-related data.

Acceptance Criteria

• A new Django management command called lp_load is added.
• The command accepts a ZIP file generated by lp_dump.
• The ZIP contents can be processed either:
  • In memory, or
  • Extracted into a temporary folder.
• At this stage, only the Learning Package content is restored.