Clean up and document project files (#4560)

docs/mkdocs/requirements.txt

@@ -1,6 +1,11 @@
+wheel==0.45.1
+
 mkdocs==1.6.1                                       # documentation framework
 mkdocs-git-revision-date-localized-plugin==1.3.0    # plugin "git-revision-date-localized"
 mkdocs-material==9.5.49                             # theme for mkdocs
 mkdocs-material-extensions==1.3.1                   # extensions
 mkdocs-minify-plugin==0.8.0                         # plugin "minify"
 mkdocs-redirects==1.2.2                             # plugin "redirects"
+mkdocs-htmlproofer-plugin==1.3.0                    # plugin "htmlproofer"
+
+PyYAML==6.0.2                                       # linter