Reorganize frontend files and tooling (#10168)

- move "vendor" files to js/vendor and less/vendor
- move swagger to js/standalone (meant for standalone pages)
- move gitgraph to features and streamline its loading
- add linting configs to webpack dependencies in make
- set ignored files for eslint/stylelint directly in their configs

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Antoine GIRARD <sapk@users.noreply.github.com>

.eslintrc

@@ -4,6 +4,9 @@ extends:
   - eslint-config-airbnb-base
   - eslint:recommended
 
+ignorePatterns:
+ - /web_src/js/vendor
+
 parserOptions:
   ecmaVersion: 2020