[zero] Refactor ZeroContextConfig class using dataclass

[yhna940]

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📝 What does this PR do?

This PR refactors the ZeroContextConfig class to use the dataclass decorator from Python's standard library. This change simplifies the code, improves readability, and reduces the possibility of bugs due to human error.

Motivation:

The dataclass decorator provides a more concise way to define classes with simple attributes, such as the configuration class.
It automatically generates common special methods, such as __init__, __repr__, and __eq__, reducing the need for boilerplate code.
Using dataclass also makes the code more Pythonic and easier to maintain.

Changes:

Refactor ZeroContextConfig class to use dataclass decorator
Update constructor arguments and their documentation
Add __post_init__ method for additional assertions
Please review and let me know if any changes are required. Thanks!

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