Correctly coerce Parquet Int96 timestamps into requested TimeUnits

[jaychia]

Addresses the first part of issue #1527

Instead of always naively parsing Parquet Int96 timestamps into TimeUnit::Nanosecond, we match on the requested timeunit and perform timeunit-specific parsing

This makes parsing safer when reading Int96 timestamps that are outside of the range of timestamp[ns] (e.g. timestamps with dates like the years 1000 or 3000) instead of the current behavior which is to always parse the timestamps with the Nanosecond timeunit, and overflow.

[jaychia]

Also happy to move the int96_to_i64_*s logic over into the parquet2 repo!

[ritchie46]

Also happy to move the int96_toi64*s

I believe that all arrow datatype related conversions are done here, so that is fine.

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.66% :warning:

Comparison is base (b09e580) 83.73% compared to head (b749735) 83.07%. Report is 49 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1532 +/- ## ========================================== - Coverage 83.73% 83.07% -0.66% ========================================== Files 389 389 Lines 41811 42632 +821 ========================================== + Hits 35009 35417 +408 - Misses 6802 7215 +413 ``` | [Files Changed](https://app.codecov.io/gh/jorgecarleitao/arrow2/pull/1532?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jorge+Leitao) | Coverage Δ | | |---|---|---| | [src/io/parquet/read/deserialize/simple.rs](https://app.codecov.io/gh/jorgecarleitao/arrow2/pull/1532?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jorge+Leitao#diff-c3JjL2lvL3BhcnF1ZXQvcmVhZC9kZXNlcmlhbGl6ZS9zaW1wbGUucnM=) | `86.27% <100.00%> (+1.76%)` | :arrow_up: | ... and [54 files with indirect coverage changes](https://app.codecov.io/gh/jorgecarleitao/arrow2/pull/1532/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jorge+Leitao)

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[jaychia]

Second PR is up! #1533

[jaychia]

@ritchie46 any chance you could retrigger CI - Seems to be failing on some flaky token issues?

{'detail': ErrorDetail(string='Unable to locate build via Github Actions API. Please upload with the Codecov repository upload token to resolve issue.', code='not_found')}

[jaychia]

Thanks for the stamp @sundy-li!

I had to make a new PR to fix lints since they were re-enabled last week. Would appreciate some help with launching CI :)

[sundy-li]

Merged, will create a new pr to fix the clippy.