Remove pickling demo and include other minor fixes

[jaggiK]

This PR addresses the following updates:

Removal of Pickling Demo: The demo for pickling states has been removed as it is currently broken.
Dependencies: Included a pip install instruction for Adalflow to streamline dependencies.
Import Fixes: Fixed import issues for Parameter and Sequential to ensure compatibility and proper functionality.
OpenAI API Key Entry: Enabled API key entry via keyboard input, aligning with the interaction method in other notebooks.

Testing:
This PR has been tested successfully on both a local machine and Google Colab to verify functionality.

Notes:
The pickling demo can be reintroduced in the future once the issues are resolved. More on this issue can be found here

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[liyin2015]

@jaggiK appreciate your contribution. This is great, but this would be even better for us and be more final:

For every tutorial, like the screenshot, we provide two files to complement the documentation:

• .py code located in /tutorials
• .ipynb (auto-converted to colab) located in /notebooks/tutorials (name it adalflow_component.ipynb)

Thus, we would appreciate you can do this:

• convert the component.ipynb code to component.py
• create adalflow_component.ipynb in notebooks/tutorials
• Replace the link in colab tutorial http://adalflow.sylph.ai/ . The new link you can find in the README.md of notebooks dir

Let me know if this make sense to you @jaggiK

@fm1320 for context on working on documentation

[jaggiK]

Could you provide further clarification on the third point? I've made some changes based on my understanding, let me know if I've misinterpreted the requirement.

[fm1320]

@jaggiK Hi, basically you need to edit the docs/source/tutorials files so that the links appear as part of the documentation. So that they appear here like open in colab:

More info in the contributing guide here: https://adalflow.sylph.ai/contributor/contribution.html