refactor(consume): move test execution files to shared hive_tests directory

Consolidate test_via_engine.py and test_via_rlp.py into a shared hive_tests/
directory to improve organization and prepare for future multi-client architectures.

- Create src/pytest_plugins/consume/simulators/hive_tests/ directory.
- Move test_via_engine.py from engine/ to hive_tests/.
- Move test_via_rlp.py from rlp/ to hive_tests/.
- Update get_command_paths() to reference new locations.
- Maintain separation: plugin configs (conftest.py) stay with their simulators.

This provides better logical organization of test execution files while
maintaining explicit pytest plugin structure.

Author: danceratopz