feat: add gemini realtime and speaches integration

- Add gemini realtime support
- Add speaches support for locally hosted LLMs

api/schemas/user_configuration.py

@@ -5,6 +5,7 @@ from pydantic import BaseModel
 from api.services.configuration.registry import (
     EmbeddingsConfig,
     LLMConfig,
+    RealtimeConfig,
     STTConfig,
     TTSConfig,
 )
@@ -15,6 +16,8 @@ class UserConfiguration(BaseModel):
     stt: STTConfig | None = None
     tts: TTSConfig | None = None
     embeddings: EmbeddingsConfig | None = None
+    realtime: RealtimeConfig | None = None
+    is_realtime: bool = False
     test_phone_number: str | None = None
     timezone: str | None = None
     last_validated_at: datetime | None = None