Refactor backend to support interface-definition driven model resources

- Introduce a new model structure for managing interface definitions and model resources, enhancing the backend's capability to handle various service integrations.
- Update the Makefile to reflect changes in database seeding and resource management commands.
- Remove the deprecated credentials management routes and replace them with a unified model registry API.
- Modify existing routes and schemas to align with the new model structure, ensuring seamless integration with the frontend.
- Enhance database seeding scripts to populate new model resources and their configurations.
- Update README documentation to reflect the new architecture and usage instructions for model resources and interface definitions.

backend/models.py

@@ -31,8 +31,15 @@ class AssistantConfig(BaseModel):
     stt_language: str = ""
     tts_speed: float = 1.0
     realtimeModel: str = ""
-    stt_interface_type: str = "openai"
-    tts_interface_type: str = "openai"
+    llm_interface_type: str = "openai-llm"
+    stt_interface_type: str = "openai-asr"
+    tts_interface_type: str = "openai-tts"
+    llm_values: dict = {}
+    llm_secrets: dict = {}
+    stt_values: dict = {}
+    stt_secrets: dict = {}
+    tts_values: dict = {}
+    tts_secrets: dict = {}
 
     enableInterrupt: bool = True