Add a migration guide from pip to uv projects (#12382)
[Rendered](https://github.com/astral-sh/uv/blob/zb/pip-wip/docs/guides/migration/pip-to-project.md)
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Co-authored-by: samypr100 <3933065+samypr100@users.noreply.github.com>
Co-authored-by: Mathieu Kniewallner <mathieu.kniewallner@gmail.com>
Co-authored-by: Aria Desires <aria.desires@gmail.com>
