Fix npm audit report, remove gulp-plumber, gulp-sass-lint and stylelint packages

Here is a patch.

npm/pnpm audit is now reporting just "glob-parent / high / install >=5.1.2" which we can not update for now because of gulp.

I've decided to remove gulp-sass-lint because is not maintained anymore, and we are not using it. It is using old version of minimist, acorn, merge, shelljs.
If we need linter it in the future we will replace it with something better - I think that core started pushing linter configurations with modern tools for CSS and JS which we should use if we want linters support.

Remove all stylelint packages - they are blocking update of various modules, and we are not using stylelint for now. Same decision as for gulp-sass-lint.

We can remove gulp-plumber package because we are not using it.

ajv we can remove when we remove gulp-sass-lint and all stylelint packages.

jsonpointer we can remove when we remove gulp-sass-lint.

Committed.

Automatically closed - issue fixed for 2 weeks with no activity.