arrow

GH-34737: [C#] C Data interface for schemas and types (#34133)

### Rationale for this change

This starts the C Data Interface implementation for C# with integration for `ArrowSchema`. `ArrowArray` will come in a follow-up PR.

### What changes are included in this PR?

* Adds classes `CArrowSchema` and `ImportedArrowSchema` which allow interacting with the `CArrowSchema`.
* Adds integration tests with PyArrow, inspired by the similar integration tests in [arrow-rs](https://github.com/apache/arrow-rs/blob/master/arrow/src/pyarrow.rs)

### Are these changes tested?

Yes, the PyArrow integration tests validate the functionality.

### Are there any user-facing changes?

This only adds new APIs, and doesn't change any existing ones.

* Closes: #33856
* Closes: #34737

Lead-authored-by: Will Jones <willjones127@gmail.com>
Co-authored-by: Weston Pace <weston.pace@gmail.com>
Signed-off-by: Eric Erhardt <eric.erhardt@microsoft.com>