Refactor queue system into modular structure

- Created new queue module with separate components:
  - models.py: QueueItem and QueueMetrics data classes
  - persistence.py: Queue state persistence
  - monitoring.py: Health monitoring and metrics
  - cleanup.py: Cleanup operations
  - manager.py: Main queue management
  - __init__.py: Package exports

- Updated imports in video_archiver.py and processor.py
- Removed old enhanced_queue.py
- Updated README with new queue system details

This refactoring improves code organization and maintainability
through better separation of concerns while maintaining all
existing functionality.

videoarchiver/queue/__init__.py

@@ -0,0 +1,19 @@
+"""Queue management package for video processing"""
+
+from .models import QueueItem, QueueMetrics
+from .manager import EnhancedVideoQueueManager
+from .persistence import QueuePersistenceManager, QueueError
+from .monitoring import QueueMonitor, MonitoringError
+from .cleanup import QueueCleaner, CleanupError
+
+__all__ = [
+    'QueueItem',
+    'QueueMetrics',
+    'EnhancedVideoQueueManager',
+    'QueuePersistenceManager',
+    'QueueMonitor',
+    'QueueCleaner',
+    'QueueError',
+    'MonitoringError',
+    'CleanupError',
+]