OAI: Implement completion API endpoint

Add support for /v1/completions with the option to use streaming
if needed. Also rewrite API endpoints to use async when possible
since that improves request performance.

Model container parameter names also needed rewrites as well and
set fallback cases to their disabled values.

Signed-off-by: kingbri <bdashore3@proton.me>

OAI/utils.py

@@ -0,0 +1,19 @@
+from OAI.models.completions import CompletionResponse, CompletionRespChoice
+from OAI.models.common import UsageStats
+from typing import Optional
+
+def create_completion_response(text: str, index: int, model_name: Optional[str]):
+    # TODO: Add method to get token amounts in model for UsageStats
+
+    choice = CompletionRespChoice(
+        finish_reason="Generated",
+        index = index,
+        text = text
+    )
+
+    response = CompletionResponse(
+        choices = [choice],
+        model = model_name or ""
+    )
+
+    return response