[bazel-6] Convert docs build to basic webpack

[adierkens]

Far from perfect & optimized (we should still try to leverage nextjs/remix if possible, and generate a proper static site).
This gets us a working docs site using bazel-6/rules_js & react@18.

chakra-ui wasn't playing nicely with nextjs + react@18, and the options were to either replace nextjs or chakra -- and the path of least resistance was to swap out nextjs temporarily. The docs site should look and behave the same as it did prior, just with less optimizations.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.71%. Comparing base (98a8d91) to head (ad4a93a).
Report is 4 commits behind head on bazel-6.

Additional details and impacted files

@@           Coverage Diff            @@
##           bazel-6     #327   +/-   ##
========================================
  Coverage    91.70%   91.71%           
========================================
  Files          332      332           
  Lines        26731    26729    -2     
  Branches      1935     1935           
========================================
  Hits         24514    24514           
+ Misses        2203     2202    -1     
+ Partials        14       13    -1     

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