feat: Add IpynbConverter

[AumGupta]

• Implemented IpynbConverter class for converting Jupyter Notebook (.ipynb) files into Markdown format.
• Supports markdown cells, code cells and raw cells.
• First markdown heading is used as the title if no title is found in notebook metadata.
• Created a test notebook (test_notebook.ipynb) to verify the functionality of the converter.

[AumGupta]

@microsoft-github-policy-service agree

[afourney]

This is pretty cool, and I like that it doesn't really add any new dependencies (since it's all just json).

[afourney]

Looks like a small formatting error.

Can you do a:

pre-commit install
pre-commit run --all-files

And then re-commit / push _markitdown.py? Very likely, the formatting will be corrected automatically.

[AumGupta]

Looks like a small formatting error.

Can you do a:

pre-commit install
pre-commit run --all-files

And then re-commit / push _markitdown.py? Very likely, the formatting will be corrected automatically.

@afourney brother, I've done it.