chore: clean up unnecessary code/files

[myungjin]

Description

There exist outdated code and files, which are not compatible with the current API in world_manager and world_communicator. Those code and files are removed.

Type of Change

• [ ] Bug Fix
• [ ] New Feature
• [ ] Breaking Change
• [x] Refactor
• [ ] Documentation
• [ ] Other (please describe)

Checklist

• [ ] I have read the contributing guidelines
• [ ] Existing issues have been referenced (where applicable)
• [ ] I have verified this change is not present in other open pull requests
• [ ] Functionality is documented
• [ ] All code style checks pass
• [ ] New code contribution is covered by automated tests
• [ ] All new and existing tests pass