[PYG-203] 🦬 Split data class core

[doctrino]

Description

Please describe the change you have made.

Checklist:

• Tests added/updated.
• Documentation updated.
• Changelog updated in CHANGELOG.md.
• Version bumped. If triggering a new release is desired (?), bump the version number by running python dev.py bump --patch (replace --patch with --minor or --major per semantic versioning).
• Regenerate example SDKs export PYTHONPATH=. && python dev.py generate. Need to be run both
  for pydantic v1 and v2 environments.

[github-actions]

☂️ Python Coverage

current status: ✅

Overall Coverage

Lines	Covered	Coverage	Threshold	Status
3757	2464	66%	60%	🟢

New Files

File	Coverage	Status
cognite/pygen/_core/templates/data_classes_core_constants.py.jinja	100%	🟢
cognite/pygen/_core/templates/data_classes_core_helpers.py.jinja	14%	🟢
cognite/pygen/_core/templates/data_classes_core_init.py.jinja	75%	🟢
cognite/pygen/_core/templates/data_classes_core_query.py.jinja	2%	🟢
TOTAL	48%	🟢

Modified Files

File	Coverage	Status
cognite/pygen/_core/generators.py	94%	🟢
TOTAL	94%	🟢

updated for commit: 02c0571 by action🐍