ARROW-11259: [Python] Allow to create field reference to nested field

[AlenkaF]

This PR tries to redo the work from #9799.

It will unblock:

• https://issues.apache.org/jira/browse/ARROW-13798
• https://issues.apache.org/jira/browse/ARROW-14596

cc @jorisvandenbossche@pitrou

[github-actions]

https://issues.apache.org/jira/browse/ARROW-11259

[github-actions]

⚠️ Ticket has not been started in JIRA, please click 'Start Progress'.

[lidavidm]

LGTM, thank you! I left a couple thoughts.

[pitrou]

Do we have to spell out field_ref(FieldRef("foo", "bar")) explicitly or is it possible to simply write field_ref("foo", "bar")?

[AlenkaF]

Will try to simplify.

[AlenkaF]

Currently it doesn't work, FieldRef("foo", "bar") needs to be spelled out.

Try 1: `field_ref("foo", "bar")`

```
/Users/alenkafrim/repos/arrow/cpp/src/arrow/compute/exec/expression_test.cc:1379:20: error: no matching function for call to 'field_ref'
ExpectRoundTrips(field_ref("foo", "bar", "baz"));
^~~~~~~~~
/Users/alenkafrim/repos/arrow/cpp/src/arrow/compute/exec/expression.h:152:12: note: candidate function not viable: requires single argument 'ref', but 3 arguments were provided
Expression field_ref(FieldRef ref);
```

Try 2: `field_ref(("foo", "bar"))`

```
/Users/alenkafrim/repos/arrow/cpp/src/arrow/compute/exec/expression_test.cc:1379:31: warning: expression result unused [-Wunused-value]
ExpectRoundTrips(field_ref(("foo", "bar", "baz")));
```

[AlenkaF]

Thank you for the comments @lidavidm@pitrou!
I think this PR is ready for another round of review (the errors should be related to the S3fs) .

[pitrou]

Thanks for the update @AlenkaF ! Just two minor comments.

[pitrou]

+1, will merge if green. Thank you @AlenkaF !

[ursabot]

Benchmark runs are scheduled for baseline = 83dda5c and contender = e0668e2. e0668e2 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 ⬇️0.5% ⬆️0.04%] test-mac-arm
[Failed ⬇️0.0% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.26% ⬆️0.0%] ursa-thinkcentre-m75q
Buildkite builds:
[Finished] <https://buildkite.com/apache-arrow/arrow-bci-benchmark-on-ec2-t3-xlarge-us-east-2/builds/524|e0668e20 ec2-t3-xlarge-us-east-2>
[Failed] <https://buildkite.com/apache-arrow/arrow-bci-benchmark-on-test-mac-arm/builds/511|e0668e20 test-mac-arm>
[Failed] <https://buildkite.com/apache-arrow/arrow-bci-benchmark-on-ursa-i9-9960x/builds/510|e0668e20 ursa-i9-9960x>
[Finished] <https://buildkite.com/apache-arrow/arrow-bci-benchmark-on-ursa-thinkcentre-m75q/builds/521|e0668e20 ursa-thinkcentre-m75q>
[Finished] <https://buildkite.com/apache-arrow/arrow-bci-benchmark-on-ec2-t3-xlarge-us-east-2/builds/523|83dda5c3 ec2-t3-xlarge-us-east-2>
[Failed] <https://buildkite.com/apache-arrow/arrow-bci-benchmark-on-test-mac-arm/builds/510|83dda5c3 test-mac-arm>
[Failed] <https://buildkite.com/apache-arrow/arrow-bci-benchmark-on-ursa-i9-9960x/builds/509|83dda5c3 ursa-i9-9960x>
[Finished] <https://buildkite.com/apache-arrow/arrow-bci-benchmark-on-ursa-thinkcentre-m75q/builds/520|83dda5c3 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