ARROW-14094: [C++] add(timestamp, duration) -> timestamp kernel

[rok]

This is to resolve ARROW-14094.

[github-actions]

https://issues.apache.org/jira/browse/ARROW-14094

[lidavidm]

TimestampType and DurationType are both int64_t underneath, is it possible to reuse the existing Exec method? (i.e. does ArithmeticExecFromOp<ScalarBinary, Add>(Type::INT64) work here?)

[rok]

It works for ScalarBinaryEqualTypes but not for ScalarBinary as it takes in and out types.
auto exec = ArithmeticExecFromOp<ScalarBinaryEqualTypes, Add>(Type:: INT64); would work.

We could add ArithmeticExecFromOpEqualTypes.

[lidavidm]

Ah, I think it's not too big a deal then.

[ursabot]

Benchmark runs are scheduled for baseline = ec3608c and contender = e31189f. e31189f 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
[Finished ⬇️0.21% ⬆️0.17%] test-mac-arm
[Failed ⬇️0.0% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.43% ⬆️0.0%] ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python. 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