[DOCS] Fix docs to add SQL capabilities

[jaychia]

1. Changes a lot of the messaging in Daft to talk about us as a data engine that exposes both a SQL and Python API

[codspeed-hq]

CodSpeed Performance Report

Merging #2931 will not alter performance

_{Comparing jay/docs-sql-overhaul (75b7acb) with main (a2be8a3)}

Summary

✅ 17 untouched benchmarks

[github-actions]

🚀 Deployed on https://deploy-preview-2931--daft-docs-preview.netlify.app

[codecov]

Codecov Report

Attention: Patch coverage is 83.96226% with 51 lines in your changes missing coverage. Please review.

Project coverage is 78.31%. Comparing base (868bbfa) to head (75b7acb).
Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
src/daft-sql/src/python.rs	0.00%	25 Missing ⚠️
daft/sql/_sql_funcs.py	0.00%	16 Missing ⚠️
src/daft-sql/src/modules/utf8.rs	89.83%	6 Missing ⚠️
src/daft-sql/src/functions.rs	71.42%	2 Missing ⚠️
src/daft-sql/src/modules/aggs.rs	85.71%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2931      +/-   ##
==========================================
- Coverage   78.71%   78.31%   -0.41%     
==========================================
  Files         597      599       +2     
  Lines       69735    71213    +1478     
==========================================
+ Hits        54895    55769     +874     
- Misses      14840    15444     +604     

Flag	Coverage Δ
	78.31% <83.96%> (-0.41%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
daft/sql/sql.py	97.61% <100.00%> (-0.21%)	⬇️
src/daft-sql/src/modules/float.rs	94.20% <100.00%> (+3.09%)	⬆️
src/daft-sql/src/modules/image/crop.rs	33.33% <100.00%> (+33.33%)	⬆️
src/daft-sql/src/modules/image/decode.rs	13.04% <100.00%> (+13.04%)	⬆️
src/daft-sql/src/modules/image/encode.rs	18.75% <100.00%> (+18.75%)	⬆️
src/daft-sql/src/modules/image/resize.rs	12.24% <100.00%> (+12.24%)	⬆️
src/daft-sql/src/modules/image/to_mode.rs	20.68% <100.00%> (+20.68%)	⬆️
src/daft-sql/src/modules/json.rs	84.00% <100.00%> (+5.05%)	⬆️
src/daft-sql/src/modules/list.rs	90.26% <100.00%> (+3.51%)	⬆️
src/daft-sql/src/modules/map.rs	45.45% <100.00%> (+20.45%)	⬆️
... and 9 more

... and 30 files with indirect coverage changes

[universalmind303]

a few small changes, but overall looks good!