feat: Refactor log-alert application into modular structure

- Introduced alerters package with base Alerter class and implementations for LogAlerter and GotifyAlerter.
- Created fetchers package with abstract LogFetcher class and implementations for FileLogFetcher, LokiLogFetcher, and ParseableLogFetcher.
- Added filters package with base Filter class and implementations for RegexpFilter and GeolocationFilter.
- Implemented rules package with base AlertRule class and SimpleAlertRule for alerting logic.
- Enhanced configuration handling with utilities for loading and validating JSON configuration.
- Updated logging setup for better logging management.
- Modified main application logic to utilize the new modular structure, improving maintainability and readability.
- Updated config.json and config.schema.json to reflect changes in alerting and fetching configurations.
- Added python-dateutil to requirements for date parsing functionality.

log-alert/utils/__init__.py

@@ -0,0 +1,12 @@
+"""Utilities package for log-alert."""
+
+from .config import load_config, validate_config_with_schema, update_config_from_env
+from .logging import setup_logging, get_logger
+
+__all__ = [
+    "load_config",
+    "validate_config_with_schema",
+    "update_config_from_env",
+    "setup_logging",
+    "get_logger",
+]