Reuse the requirements.txt installation logic from sagemaker-inference-toolkit

[humanzz]

Describe the feature you'd like

sagemaker-inference-toolkit is in the middle of introducing support for installing requirements.txt dependencies from CodeArtifact in aws/sagemaker-inference-toolkit#130

Additional context

• https://github.com/aws/sagemaker-pytorch-inference-toolkit/blob/master/src/sagemaker_pytorch_serving_container/torchserve.py#L81 is identical to https://github.com/aws/sagemaker-inference-toolkit/blob/master/src/sagemaker_inference/model_server.py#L82

• Reusing the logic from sagemaker-inference-toolkit would allow sagemaker pytorch containers to get the support for CodeArtifact