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GH-17682: [C++][Python] Bool8 Extension Type Implementation (#43488)



### Rationale for this change

C++ and Python implementations of #43234

### What changes are included in this PR?

- Implement C++ `Bool8Type`, `Bool8Array`, `Bool8Scalar`, and tests
- Implement Python bindings to C++, as well as zero-copy numpy conversion methods
- TODO: docs waiting for rebase on #43458

### Are these changes tested?

Yes

### Are there any user-facing changes?

Bool8 extension type will be available in C++ and Python libraries

* GitHub Issue: #17682

Authored-by: Joel Lubinitsky <joellubi@gmail.com>
Signed-off-by: Felipe Oliveira Carvalho <felipekde@gmail.com>