* chore: add GN linter
* chore: fix GN lint errors
* try some crazy bash to get a gn exe
* base64 on linux is different
* cloning build_tools doesn't download GN
* download_from_google_storage needs depot_tools in the path
* fixup! chore: add GN linter
* refactor: use one script to launch py, js, cc linters
* lint changed files as precommit hook
* fix py linter in GN build
* add overlooked files to linter search path
