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GH-17682: [Go] Bool8 Extension Type Implementation (#43323)



### Rationale for this change

Go implementation of #43234

### What changes are included in this PR?

- Go implementation of the `Bool8` extension type
- Minor refactor of existing extension builder interfaces

### Are these changes tested?

Yes, unit tests and basic read/write benchmarks are included.

### Are there any user-facing changes?

- A new extension type is added
- Custom extension builders no longer need another builder created and released separately.

* GitHub Issue: #17682

Authored-by: Joel Lubinitsky <joellubi@gmail.com>
Signed-off-by: Joel Lubinitsky <joellubi@gmail.com>