feat: Use geoarrow-c for input functionality

[paleolimbot]

No description provided.

[codecov-commenter]

Codecov Report

Attention: 276 lines in your changes are missing coverage. Please review.

Comparison is base (73cbf9a) 32.71% compared to head (5f6adf8) 28.04%.

Files	Patch %	Lines
src/s2geography/geoarrow.cc	4.62%	268 Missing ⚠️
src/s2geography/geoarrow.h	0.00%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #16      +/-   ##
==========================================
- Coverage   32.71%   28.04%   -4.67%     
==========================================
  Files          14       16       +2     
  Lines        1458     1747     +289     
  Branches       28       35       +7     
==========================================
+ Hits          477      490      +13     
- Misses        973     1249     +276     
  Partials        8        8              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[jorisvandenbossche]

Small question: the title of the PR mentions "input/output", but is my reading correct that at the moment this PR only adds the "input" part? (there only seems to be a reader that goes from any sort of ArrowArray to a vector of Geography objects)

[paleolimbot]

I need to revisit this PR! I think the output part is actually much easier than the input part, and that the goal of this PR is to remove the shim I had added earlier that was a previous (and untested) version of a C++ geoarrow library. In order to remove that shim, I think it would have to handle both.

[jorisvandenbossche]

Small point of feedback, regarding the code structure: IMO it would be clearer if you put the geoarrow code in e.g. a vendored/ subdirectory (like we do in arrow/cpp), that will make it more obvious that this is vendored code not and not maintained here.
And maybe also include a README in there that briefly mentions this and lists which functionality it provides that is used by s2geography.

[paleolimbot]

I think the output part is actually much easier than the input part

I still think this is true, but I'll merge this to hopefully unblock some of the things you are working on. For both input and output it may be worth avoiding geoarrow-c here, but at least this gets to a place where we can write tests and then improve the implementation. (All of this is code I wrote a long time ago!)