Add specific parameter handling for SD Turbo model

Fix environment variable name from MODEL_ID to MODEL for Hugging Face Spaces

Switch to SDXL base model for better InferenceClient compatibility

Switch to SDXL Turbo model and fix parameters

Enhance FastAPI application to support image generation with Inference API. Updated API title, added model configuration, and implemented a new endpoint for generating images from text prompts. Retained echo functionality for testing.

Add FastAPI application with Docker support