ARROW-5248: [Python] support zoneinfo / dateutil timezones

[AlenkaF]

This PR tries to add support for zoneinfo and dateutil timezones.

• Add support for the zoneinfo
• Add tests for zoneinfo support
• Add support for dateutil
• Add tests for dateutil support

[github-actions]

https://issues.apache.org/jira/browse/ARROW-5248

[jorisvandenbossche]

This is looking good!

From talking about it:

• Dateutil is optional dependency, and zoneinfo only available from Python 3.9 onwards, so in C++ we (for now) can remove the imports
• The tests will need to add a skip if the package is not available (pytest has a importorskip helper that can be used for this)

[AlenkaF]

Thanks for reviewing Joris! Currently:

• imports are removed
• test is split and skipped in case zoneinfo is not available
• comments for the check in case of zoneinfo and dateutil objects are added

I would leave the handling of zoneinfo and dateutil objects in TzinfoToString as is (looking up 'key' and '_filename' attribute) and plan to restructure (to check for an instance of the object) together with pytz change for https://issues.apache.org/jira/browse/ARROW-15580.

There is a CI error with appveyor: 43 - arrow-dataset-file-csv-test (Failed) in ctest. Don't know what would cause that -will look into it a bit more.

[jorisvandenbossche]

There is a CI error with appveyor: 43 - arrow-dataset-file-csv-test (Failed) in ctest. Don't know what would cause that -will look into it a bit more.

That looks like an unrelated error (although I don't see it happening on master). I restarted Appveyor to see if that fixes it.

[AlenkaF]

@jorisvandenbossche it looks like the error on Travis isn't connected, so this PR should be ready.

[AlenkaF]

@jorisvandenbossche unrelated Ci issue again, I think ...

[jorisvandenbossche]

Thanks!

[ursabot]

Benchmark runs are scheduled for baseline = 094c5ba and contender = 82f8ee3. 82f8ee3 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️25.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Finished ⬇️0.17% ⬆️0.0%] test-mac-arm
[Finished ⬇️0.71% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.0% ⬆️0.04%] 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