[inference] add llama2 support

[Xu-Kai]

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📝 What does this PR do?

• Support llama2

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[github-actions]

The code coverage for the changed files is 16%.

Click me to view the complete report

Name                                                      Stmts   Miss  Cover
-----------------------------------------------------------------------------
colossalai/inference/tensor_parallel/engine.py              177    147    17%
colossalai/inference/tensor_parallel/modeling/_utils.py      33     33     0%
colossalai/inference/tensor_parallel/modeling/llama.py      161    161     0%
colossalai/kernel/triton/__init__.py                         16      3    81%
tests/test_infer/test_llama2_infer.py                        40     14    65%
-----------------------------------------------------------------------------
TOTAL                                                       427    358    16%