Add pycjs, the python caller of js based on node_vm2

[birdflyi]

Fix #1463

Purpose

• Add a more low maintenance costs and safer python kernel to replace the old kernel python and python_v2.

Changes

• Add Func: Add the python caller of js 'pycjs' with the node_vm2 sandbox environment.
• Add a python kernel ipynb to call functions in the open_digger module as a simple example.

Notes

• pycjs_node_vm.py is the core of pycjs. It can be used for other projects similar to the js2py type.
• The parameter kwargs of function get_export_module offer many display options for the variable df_export_module, which is useful when you want to know if a function is available or to lookup the call path of the functions.
• We need no migration of the changes to Python kernel as metioned in https://github.com/X-lab2017/open-digger/issues/1478#issue-2072446725 anymore：This kernel uses a virtual machine to run JavaScript functions, and only exposes function call handles in the sandbox.

[frank-zsy]

All looks good, I will merge the PR first and we should encourage developers to use this new kernel lib to find out if it works fine as well.

[birdflyi]

I completely agree~