Description

Modernized model fields in models.py as suggested in #863:

• Replaced default=datetime.now with db_default=Now() for all DateTimeField fields, moving defaults to the database level and fixing naive datetime usage (Django 5.0+)
• Replaced CharField with GenericIPAddressField for Sensor.address, TorExitNode.ip_address, and MassScanner.ip_address
• Removed redundant blank=False and null=False declarations since False is already the default in Django
• Updated tests in test_sensor_repository.py to remove redundant database filter assertions for invalid IPs since GenericIPAddressField enforces IP validation at the database level

Note: FireHolList.ip_address was intentionally kept as CharField since it stores both plain IPs and CIDR ranges (e.g. 1.2.3.4/24) which are incompatible with GenericIPAddressField.

Related issues

Closes #863

Type of change

• New feature (non-breaking change which adds functionality).

Checklist

• I have read and understood the rules about how to Contribute to this project.
• The pull request is for the branch develop.
• I have added documentation of the new features.
• Linter (Ruff) gave 0 errors.
• I have added tests for the feature/bug I solved. All the tests (new and old ones) gave 0 errors.
• If changes were made to an existing model/serializer/view, the docs were updated and regenerated.