GH-34171: [Go][Compute] Implement "Unique" kernel

[zeroshade]

Rationale for this change

Implementing a kernel for computing the "unique" values in an arrow array, primarily for use in solving #33466.

What changes are included in this PR?

Adds a "unique" function to the compute list and helper convenience functions.

Are these changes tested?

Yes, unit tests are included.

Are there any user-facing changes?

Just the new available functions.

• Closes: [Go][Compute] Add kernel for "unique" function #34171

[github-actions]

• Closes: [Go][Compute] Add kernel for "unique" function #34171

[ursabot]

Benchmark runs are scheduled for baseline = 266f166 and contender = 90071cc. 90071cc is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Failed ⬇️0.61% ⬆️0.0%] test-mac-arm
[Finished ⬇️0.0% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.16% ⬆️0.03%] ursa-thinkcentre-m75q
Buildkite builds:
[Finished] 90071ccd ec2-t3-xlarge-us-east-2
[Failed] 90071ccd test-mac-arm
[Finished] 90071ccd ursa-i9-9960x
[Finished] 90071ccd ursa-thinkcentre-m75q
[Finished] 266f1666 ec2-t3-xlarge-us-east-2
[Failed] 266f1666 test-mac-arm
[Finished] 266f1666 ursa-i9-9960x
[Finished] 266f1666 ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java

[ursabot]

['Python', 'R'] benchmarks have high level of regressions.
test-mac-arm