Accelerating model deployment: 100X faster dev loops with development deployments

Introduced 'development deployments' for Truss, enabling live reload of model code. This feature allows for hot-swapping code changes (e.g., pre-processing functions) without restarting the model serving environment, reducing the dev loop from minutes to seconds. Development deployments function like published deployments with their own API endpoints and special autoscaling settings for cost savings during experimentation, and can be promoted to production.