[Misc] Add SPDX-License-Identifier headers to python source files (#12628)

- **Add SPDX license headers to python source files**
- **Check for SPDX headers using pre-commit**

commit 9d7ef44c3cfb72ca4c32e1c677d99259d10d4745
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:18:24 2025 -0500

    Add SPDX license headers to python source files
    
This commit adds SPDX license headers to python source files as
recommended to
the project by the Linux Foundation. These headers provide a concise way
that is
both human and machine readable for communicating license information
for each
source file. It helps avoid any ambiguity about the license of the code
and can
    also be easily used by tools to help manage license compliance.
    
The Linux Foundation runs license scans against the codebase to help
ensure
    we are in compliance with the licenses of the code we use, including
dependencies. Having these headers in place helps that tool do its job.
    
    More information can be found on the SPDX site:
    
    - https://spdx.dev/learn/handling-license-info/

Signed-off-by: Russell Bryant <rbryant@redhat.com>

commit 5a1cf1cb3b80759131c73f6a9dddebccac039dea
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:36:32 2025 -0500

    Check for SPDX headers using pre-commit
Signed-off-by: Russell Bryant <rbryant@redhat.com>

---------
Signed-off-by: Russell Bryant <rbryant@redhat.com>

examples/offline_inference/vision_language_embedding.py

+# SPDX-License-Identifier: Apache-2.0
 """
 This example shows how to use vLLM for running offline inference with
 the correct prompt format on vision language models for multimodal embedding.

examples/offline_inference/vision_language_multi_image.py

+# SPDX-License-Identifier: Apache-2.0
 """
 This example shows how to use vLLM for running offline inference with
 multi-image input on vision language models for text generation,

examples/offline_inference/whisper.py

+# SPDX-License-Identifier: Apache-2.0
+
 import time
 
 from vllm import LLM, SamplingParams

examples/online_serving/api_client.py

+# SPDX-License-Identifier: Apache-2.0
 """Example Python client for `vllm.entrypoints.api_server`
 NOTE: The API server is used only for demonstration and simple performance
 benchmarks. It is not intended for production use.

examples/online_serving/cohere_rerank_client.py

+# SPDX-License-Identifier: Apache-2.0
 """
 Example of using the OpenAI entrypoint's rerank API which is compatible with
 the Cohere SDK: https://github.com/cohere-ai/cohere-python

examples/online_serving/gradio_openai_chatbot_webserver.py

+# SPDX-License-Identifier: Apache-2.0
+
 import argparse
 
 import gradio as gr

examples/online_serving/gradio_webserver.py

+# SPDX-License-Identifier: Apache-2.0
+
 import argparse
 import json
 

examples/online_serving/jinaai_rerank_client.py

+# SPDX-License-Identifier: Apache-2.0
 """
 Example of using the OpenAI entrypoint's rerank API which is compatible with
 Jina and Cohere https://jina.ai/reranker

examples/online_serving/openai_chat_completion_client.py

+# SPDX-License-Identifier: Apache-2.0
+
 from openai import OpenAI
 
 # Modify OpenAI's API key and API base to use vLLM's API server.

examples/online_serving/openai_chat_completion_client_for_multimodal.py

+# SPDX-License-Identifier: Apache-2.0
 """An example showing how to use vLLM to serve multimodal models 
 and run online serving with OpenAI client.
 

examples/online_serving/openai_chat_completion_client_with_tools.py

+# SPDX-License-Identifier: Apache-2.0
 """
 Set up this example by starting a vLLM OpenAI-compatible server with tool call
 options enabled. For example:

examples/online_serving/openai_chat_completion_structured_outputs.py

+# SPDX-License-Identifier: Apache-2.0
+
 from enum import Enum
 
 from openai import OpenAI

examples/online_serving/openai_chat_completion_with_reasoning.py

+# SPDX-License-Identifier: Apache-2.0
 """
 An example shows how to generate chat completions from reasoning models
 like DeepSeekR1.

examples/online_serving/openai_chat_completion_with_reasoning_streaming.py

+# SPDX-License-Identifier: Apache-2.0
 """
 An example shows how to generate chat completions from reasoning models
 like DeepSeekR1.

examples/online_serving/openai_chat_embedding_client_for_multimodal.py

+# SPDX-License-Identifier: Apache-2.0
+
 import argparse
 import base64
 import io

examples/online_serving/openai_completion_client.py

+# SPDX-License-Identifier: Apache-2.0
+
 from openai import OpenAI
 
 # Modify OpenAI's API key and API base to use vLLM's API server.

examples/online_serving/openai_cross_encoder_score.py

+# SPDX-License-Identifier: Apache-2.0
 """
 Example online usage of Score API.
 

examples/online_serving/openai_embedding_client.py

+# SPDX-License-Identifier: Apache-2.0
+
 from openai import OpenAI
 
 # Modify OpenAI's API key and API base to use vLLM's API server.

examples/online_serving/openai_pooling_client.py

+# SPDX-License-Identifier: Apache-2.0
 """
 Example online usage of Pooling API.
 

examples/online_serving/opentelemetry/dummy_client.py

+# SPDX-License-Identifier: Apache-2.0
+
 import requests
 from opentelemetry.exporter.otlp.proto.grpc.trace_exporter import (
     OTLPSpanExporter)