Ignore .eslintrc files

According to https://eslint.org/docs/user-guide/configuring:

If you are using one configuration file and want ESLint to ignore any .eslintrc.* files, make sure to use --no-eslintrc along with the -c flag.

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/9734

Please double check: I wonder if errors could be reported because some cases are not handled anymore by the "missing" .eslintrc.*.