### Motivation and Context

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Enable the use of [OpenAI's function calling
capability](https://platform.openai.com/docs/guides/gpt/function-calling)
with SK. However, since this feature is limited to OpenAI chat
completion models, we want to do so without widespread changes to the
kernel.
 Fixes microsoft#2315 
### Description

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These notes will help understanding how your code works. Thanks! -->
- Add ability to pass functions to chat completion model via request
settings. If the model does not support function calling, this will be
ignored.
- Add OpenAIFunction class to store function information when passing to
the model. This reduces coupling with OpenAI's FunctionDefinition, but
adds an extra layer of translation.
- Add translation layer between FunctionView and OpenAIFunction to
easily utilize functions already registered with the kernel
- Add example demonstrating how to include functions, parse response,
and invoke chosen function if registered with the kernel
- Add required field to ParameterView (default false). This improves the
chances of getting correct function arguments from OpenAI.

### Contribution Checklist

<!-- Before submitting this PR, please make sure: -->

- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄
- [x] Design decisions captured in MADR

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Co-authored-by: Lee Miller <lemiller@microsoft.com>