feat(cedarling): Define `init`, `authz` and `log` interfaces

[nynymike]

Define the init, authz, and log interfaces in the Cedarling which return True and the corresponding cederling_python code to call these methods.

Identified code changes

• Rust interfaces
• Python binding to interfaces

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Test cases and code coverage

• Unit tests for rust interfaces
• Integration tests for cedarling_python

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Document the changes

• Add details to Readme.md describing how to test
• Create python docs for the SDK, e.g. what params does the init method take, available method signatures, default values.