[Infer] Serving example w/ ray-serve (multiple GPU case)

[yuanheng-zhao]

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🚨 Issue number

📝 What does this PR do?

• This PR adds necessary files for Colossal Inference serving with Ray Serve. Steps of deployment were added into README.
• This demo is used for testing and demonstrating the usage of Colossal Inference from colossalai.inference.tensor_parallel with ray serve. Serving for multiple-gpu inference is supported (e.g. tensor parallel with colossalai).

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[github-actions]

The code coverage for the changed files is 61%.

Click me to view the complete report

Name                                                        Stmts   Miss  Cover
-------------------------------------------------------------------------------
colossalai/inference/tensor_parallel/modeling/__init__.py       4      4     0%
colossalai/kernel/triton/__init__.py                           14      3    79%
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TOTAL                                                          18      7    61%