Test around cuda for non-cuda users

- made logic for model loading on non-cuda systems
- split requirements files into nvidia and other
- updated other files as necessary

requirements_nvidia.txt

@@ -0,0 +1,12 @@
+numpy>=1.24.4
+soundfile>=0.12.1
+uvicorn>=0.24.0.post1
+TTS>=0.21.3
+torch>=2.1.0+cu118
+torchaudio>=2.1.0+cu118
+fastapi>=0.104.1
+Jinja2>=3.1.2
+requests>=2.31.0
+tqdm>=4.66.1
+importlib-metadata>=4.8.1
+packaging>=23.2