Add new JS linter rules (#17699)

* Add new JS linter rules

Adds a few useful rules from eslint-plugin-github. Notable changes:

- Forbid dataset usage, its camel-casing behaviour makes it hard to
  grep for attributes.
- Forbid .then() and .catch(), we should generally prefer await for new
  code. For rare cases where they are useful, a eslint-disable-line
  directive can be set.
- Add docs js to linting

* also enable github/array-foreach

* small tweak

Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Makefile

@@ -328,7 +328,7 @@ lint: lint-frontend lint-backend
 
 .PHONY: lint-frontend
 lint-frontend: node_modules
-	npx eslint --color --max-warnings=0 web_src/js build templates *.config.js
+	npx eslint --color --max-warnings=0 web_src/js build templates *.config.js docs/assets/js
 	npx stylelint --color --max-warnings=0 web_src/less
 	npx editorconfig-checker templates