code exection class and test cases

[Bob17293729]

created code execution class and add some testcases.

[research4pan]

Add code execution for special strings generated by tool-models (agents) to call python. The basic functionality looks fine, some features are missing but can be added later

examples/tool_inference.py

• [Feature] line 20: better use HfArgumentParser, so that argument in inferencer can be supported.

scripts/run_tool.sh

• [Bug] line 1: use a huggingface model instead of a local model, otherwise other users cannot use it.

src/lmflow/pipeline/inferencer.py

• [Style] line 623, 628, 626, 632: comments and outputs in English are strongly preferred, so that contributors from different countries can understand.

tests/models/test_tool_inferencer.py

• [Style] Use set_up for function names as instructed by Google python coding style.
• [Feature] Error handling tests are recommended.

[research4pan]

LGTM