Rewrite go license generator in go (#21078)

This removes the JS dependency in the checks pipeline. JSON output is
different because the previous JS did indent the license data
differently and a JSON key was changed, but the end result is the same
as it gets re-indented by wepack.

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>

.drone.yml

@@ -90,10 +90,7 @@ steps:
   - name: checks-backend
     image: golang:1.19
     commands:
-      - curl -sL https://deb.nodesource.com/setup_18.x | bash - && apt-get -qqy install nodejs
       - make checks-backend
-    environment:
-      DEBIAN_FRONTEND: noninteractive
     depends_on: [deps-backend]
     volumes:
       - name: deps