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GH-43631: [C++] Add C++ implementation of Async C Data Interface (#44495)



### Rationale for this change
Building on #43632 which created the Async C Data Structures, this adds functions to `bridge.h`/`bridge.cc` to implement helpers for managing the Async C Data interfaces 

### What changes are included in this PR?
Two functions added to bridge.h:

1. `CreateAsyncDeviceStreamHandler` populates a `ArrowAsyncDeviceStreamHandler` and an `Executor` to provide a future that resolves to an `AsyncRecordBatchGenerator` to produce record batches as they are pushed asynchronously. The `ArrowAsyncDeviceStreamHandler` can then be passed to any asynchronous producer.
2. `ExportAsyncRecordBatchReader` takes a record batch generator and a schema, along with an `ArrowAsyncDeviceStreamHandler` to use for calling the callbacks to push data as it is available from the generator. 

### Are these changes tested?
Unit tests are added (currently only one test, more tests to be added)

### Are there any user-facing changes?
No

* GitHub Issue: #43631

Lead-authored-by: Matt Topol <zotthewizard@gmail.com>
Co-authored-by: David Li <li.davidm96@gmail.com>
Co-authored-by: Benjamin Kietzman <bengilgit@gmail.com>
Signed-off-by: Matt Topol <zotthewizard@gmail.com>