Added CMakeLists config for cmake based builds (such as esp-idf)

[jeffiel]

Thank you for creating a pull request to contribute to Adafruit's GitHub code! Before you open the request please review the following guidelines and tips to help it be more easily integrated:

• Describe the scope of your change--i.e. what the change does and what parts of the code were modified. This will help us understand any risks of integrating the code.

Added CmakeLists file

• Describe any known limitations with your change. For example if the change doesn't apply to a supported platform of the library please mention it.

None known

• Please run any tests or examples that can exercise your modified code. We strive to not break users of the code and running tests/examples helps with this process.

None

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After reviewing the guidelines above you can delete this text from the pull request.

[jeffiel]

Actually sorry this was the wrong commit.