feat: add functions to daft-connect

[universalmind303]

adds the following:

• all of spark's math functions we currently have implemented.
• all of spark's string functions we currently have implemented
• all of spark's normal functions we currently have implemented

[codspeed-hq]

CodSpeed Performance Report

Merging #3780 will degrade performances by 33.13%

_{Comparing universalmind303:spark-exprs (cc82608) with main (2063d21)}

Summary

⚡ 1 improvements
❌ 1 regressions
✅ 25 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
⚡	test_iter_rows_first_row[100 Small Files]	271.8 ms	189.8 ms	+43.16%
❌	test_show[100 Small Files]	15.9 ms	23.7 ms	-33.13%

[codecov]

Codecov Report

Attention: Patch coverage is 58.88889% with 148 lines in your changes missing coverage. Please review.

Project coverage is 77.04%. Comparing base (610bde4) to head (cc82608).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
src/daft-connect/src/functions/math.rs	56.89%	50 Missing ⚠️
src/daft-connect/src/functions/string.rs	60.00%	46 Missing ⚠️
src/daft-connect/src/functions.rs	41.17%	20 Missing ⚠️
.../daft-connect/src/functions/partition_transform.rs	28.00%	18 Missing ⚠️
src/daft-connect/src/functions/core.rs	66.66%	12 Missing ⚠️
src/daft-connect/src/functions/aggregate.rs	91.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3780      +/-   ##
==========================================
+ Coverage   75.31%   77.04%   +1.72%     
==========================================
  Files         739      745       +6     
  Lines       95170    95116      -54     
==========================================
+ Hits        71676    73280    +1604     
+ Misses      23494    21836    -1658     

Files with missing lines	Coverage Δ
src/daft-functions/src/numeric/round.rs	86.36% <100.00%> (+5.11%)	⬆️
src/daft-functions/src/python/numeric.rs	100.00% <100.00%> (ø)
src/daft-sql/src/modules/numeric.rs	78.43% <100.00%> (ø)
src/daft-connect/src/functions/aggregate.rs	91.66% <91.66%> (ø)
src/daft-connect/src/functions/core.rs	72.83% <66.66%> (-17.44%)	⬇️
.../daft-connect/src/functions/partition_transform.rs	28.00% <28.00%> (ø)
src/daft-connect/src/functions.rs	62.26% <41.17%> (-37.74%)	⬇️
src/daft-connect/src/functions/string.rs	60.00% <60.00%> (ø)
src/daft-connect/src/functions/math.rs	56.89% <56.89%> (ø)

... and 136 files with indirect coverage changes