Move eslint/stylelint to static-code tests

stylelint 16 causes a deadlock/crash in esbuild [1]. There's no movement
on that issue, and we want stylelint 16 to be able to support the
Browser Baseline 2023.

Follow 1a28b31828 and
move the linters into test/static-code. This also starts to lint files
which are outside of esbuild's realm, such as documentation and
examples.

[1] https://github.com/evanw/esbuild/issues/3542

README.md

@@ -77,7 +77,7 @@ remove manually the symlink:
 Cockpit Starter Kit uses [ESLint](https://eslint.org/) to automatically check
 JavaScript code style in `.js` and `.jsx` files.
 
-eslint is executed within every build.
+eslint is executed as part of `test/static-code`, aka. `make codecheck`.
 
 For developer convenience, the ESLint can be started explicitly by:
 
@@ -94,7 +94,7 @@ Rules configuration can be found in the `.eslintrc.json` file.
 Cockpit uses [Stylelint](https://stylelint.io/) to automatically check CSS code
 style in `.css` and `scss` files.
 
-styleint is executed within every build.
+styleint is executed as part of `test/static-code`, aka. `make codecheck`.
 
 For developer convenience, the Stylelint can be started explicitly by:
 
@@ -106,12 +106,6 @@ Violations of some rules can be fixed automatically by:
 
 Rules configuration can be found in the `.stylelintrc.json` file.
 
-During fast iterative development, you can also choose to not run eslint/stylelint.
-This speeds up the build and avoids build failures due to e. g. ill-formatted
-css or other issues:
-
-    $ ./build.js -es
-
 # Running tests locally
 
 Run `make check` to build an RPM, install it into a standard Cockpit test VM