docs: linked mkdocs & api docs

[ccmao1130]

Now all the User Guide content will be hosted on mkdocs and all the API Docs remain on sphinx docs

Dependencies to install to run locally: (cc @RCHowell)
pip install mkdocs-material (<- this one will automatically install pymdown-extensions)
pip install markdown-exec
pip install mkdocs-jupyter
pip install mkdocs-macros-plugin
pip install mkdocs-simple-hooks

mkdocs build will build both docs

• link all methods in user guide with relative path

[codspeed-hq]

CodSpeed Performance Report

Merging #3703 will degrade performances by 29.7%

_{Comparing docs-rebuild (0c90db2) with main (6b302af)}

Summary

❌ 1 regressions
✅ 26 untouched benchmarks

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

Benchmarks breakdown

	Benchmark	main	docs-rebuild	Change
❌	test_iter_rows_first_row[100 Small Files]	193.5 ms	275.2 ms	-29.7%

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.94%. Comparing base (5549d16) to head (0c90db2).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3703      +/-   ##
==========================================
+ Coverage   77.73%   77.94%   +0.21%     
==========================================
  Files         726      725       -1     
  Lines       91096    90952     -144     
==========================================
+ Hits        70811    70894      +83     
+ Misses      20285    20058     -227     

see 22 files with indirect coverage changes